Hello dear, The symptoms can be attributed to injury/ pathology in soft tissues in the shoulder joint. The lump is due to swelling in the soft tissue, secondary to the inflammatory process. Symptomatic relief can be obtained with anti inflammatory preparations, application of analgesic+muscle relaxant gel & Physiotherapy exercises as suggested by your Doctor. If symptoms still persist, kindly consult an Orthopedician for proper clinical examination. Investigation like MRI of the shoulder joint will be helpful in detecting the pathological cause for the symptoms. Wishing you a good health. Take care.