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What you have is probably Scalene Myofascial Pain Syndrome. When scalene muscle is the cause of pain, the pain is referred to (either all or a combination of) chest, inner lining of scapula (shoulder bone), shoulder, posterior and lateral sides of the arm right up to the thumb and index finger. When this muscle shortens, this can press on brachial plexus (bundle of nerves and blood vessels in the armpit) and the subclavian artery and can compress or irritate these structures and cause symptoms such as abnormal sensation, cold extremity, spasms of pain, and lymphedema (swelling of lymph channels causing swelling of arm or leg) in the involved extremity. This is a major cause of TOS. Other than this it can be inflammation of veins or phlebitis, inflammation of lymph channels or lymphangitis, deep vein thrombosis or compartment syndrome.
Do discuss this with your doctor and get yourself examined. Take care!