Any amount of pain should never be ignored. While some causes are hardly anything to worry about, others can be pretty severe and lead to more complicated problems. 

Causes of Pain under Your Left Shoulder Blade

1. Injury. Have you been exercising harder lately, or maybe you helped your neighbor carry a heavy load. Whatever the reason, injuring your shoulder blade is easy to accomplish, but the shooting pain is anything but easy to handle! Make sure not to work it any more than absolutely necessary until it recovers or you can cause long-lasting damage to it.
2. Aging. While it's hardly the prettiest fact of life, aging causes your bones to brittle and become gradually weaker and weaker. While this is completely normal, you have to take extra care. Even a minor fall, which you would have gotten up and brushed yourself off in seconds 20 years earlier, can cause a lot more damage, pain and discomfort now.
3. Wrong Sleeping Position. It sounds silly, but sleeping the wrong way is actually one of the top reasons why people complain from shoulder pains. Make sure you're comfortable in bed, particularly your neck position. A hot bath can help cure your sore shoulder muscles in this situation.
4. Cold or Flu. One of the first indicators you've caught a cold or flu is body ache. If you have a cold or flu, it's natural that your entire body feels like it weighs a ton. Heat compress on your shoulder blades may help with the pain.
5. Dislocation. Your shoulder is considered dislocated when it pops from its socket. A dislocated shoulder can be extremely painful, but a simple procedure by your doctor can replace it where it belongs.
6. Frozen Shoulder. If you don't have enough synovial fluid around your shoulder joint, you may begin to experience some pain. Any movement causes pain, so sufferers try as hard as possible not to move their shoulders -- hence why it's called a "frozen shoulder". Heat therapy, medication and some simple, low-intensity exercises can all help ease your shoulder.
7. Fracture. A shoulder fracture is one of the most painful types of shoulder pains, which covers your entire shoulder area. People who are suffering from a fractured shoulder have to undergo surgery, as well as post-surgery exercises to heal.
8. Bursitis. The bursae are sacks located between your bones and muscles filled with fluid, acting as cushions when you contract/relax your muscles. Inflated bursae, however, can cause significant pain.
9. Torn Rotator Cuff. Overusing, spraining or straining your rotator cuff can be causing your shoulder blade pain. Every movement you make uses the rotator cuff, so there's no running away from this pain.
10. Compressed Nerve. Otherwise known as a pinched nerve, this is a common cause of pain under left shoulder blade.
11. Trigger Points. Trigger points, otherwise known as knots, are the painful specific areas on your shoulder blade that form due to muscle strain and overuse. When touched, these areas can cause a lot of pain, and also ache when untouched.
12. Subscapularis Inflammation. The subscapularis is the muscle that helps you to move your arm anticlockwise or inwards. When inflamed, which is a common injury amongst athletes, pain gathers in your shoulder region and sometimes it can take a long treatment period to cure.
13. Impingement Syndrome. This condition is a result of excessive strain on your shoulder blade, where your bursa and tendons become inflamed. This can also lead to injury in your rotator cuff.
14. Other Causes
    • Gallbladder: Patients suffering from gallbladder pains will usually feel pain radiating from under the right or left shoulder blade.
    • Inflammation: Inflammation of the pancreas, pleura or pericardium can also be felt from under the right or left shoulder blade.
    • General soreness of your shoulder blades as a result of peptic or intestine ulcers.
    • As a result of a heart attack.
    • Pneumonia, pulmonary embolism or a range of other health conditions can also cause pain under your left shoulder blade.

Treatments for Pain under Left Shoulder Blade

Home Remedies

• Enough Rest. This should go without saying, but rest is imperative in the healing process. Try to take things easy and skip any tasks that put strain on your shoulders.
• Cold and Hot Compresses. Applying a cold pack on your shoulder can help ease the pain, especially if it's caused by inflammation as a result of overstretched muscles. Apply the cold pack 3 times a day over the area that is bothering you, for about 15 minutes each time. This not only helps reduce the pain, but it also helps removing the inflammation.
• Stress. Studies show that a person under stress will feel more body pain than a person who is relaxed. Taking it easy goes beyond just the physical; it's just as important to rest yourself mentally and allow yourself time to heal. If your work place is a stressful place, take time off work to recoup.
• Supplements. There are tons of vitamins and nutritional supplements you can take that will speed up the recovery process and help you regain your strength. Be sure to consult a professional before taking any supplements, though, so you can make sure that you're taking the right stuff for your condition.
• Yoga and Exercises. Low-intensity exercises can also help alleviate the pain, especially stretching exercises and yoga, which is a great way to relax shoulder muscles and clear your mind, too.
• Weight Control. Overweight people have a higher risk of suffering from shoulder pains, since the extra body weight strains their muscles. Simply losing weight can make all the difference, and also help you avoid a series of other health complications that come with obesity.
• Spinal Manipulation. Spinal manipulation is a great alternative to medical treatment that is widely regarded as a safe treatment option with little chance of any negative side effects since no drugs are used.
• Massage. Massage therapy is another no-risk method for patients suffering from shoulder pains as a result of sleeping awkwardly, bad posture or over-stretching/straining the muscles. Some of the most common types of massages include: pressure point massage, Swedish massage and shiatsu massage.
• Acupuncture. This traditional Chinese method of healing helps reduce pain and inflammation, as well as increasing energy flow. Regarded as one of the most popular old Chinese traditions, acupuncture is widely used today in not only pain relief, but also to reduce stress and help a person relax.
• Herbs. Herbal remedies are a natural way to reduce inflammation and help healing move faster, due to the antioxidants contained in them. Pomegrante, berries and acai all contain high amounts of antioxidants, while chamomile and valerian help relax your muscles and ease any aches, including pain under left shoulder blade.

Medical Treatments

• Medications. When home remedies don't work, it may be time to visit your doctor and get a prescription.
• Sling. Some doctors recommend wearing a sling for the duration of the recovery period, as it restricts movements that can delay full healing and offers added stability to your shoulder area.
• Potential Conditions Treatment. If home and natural remedies don't work, you should see your doctor as there may be underlying causes for your shoulder pain, including heart or liver disease and cancer. Don't worry before you have to though, and make sure you see your doctor to get all the appropriate tests and scans to make sure. As they say, it's better to be safe than sorry.