Hi there, Thank you for posting your question. I will do my best to help you. There are several things that can cause shoulder pain . A tendon (a band of tissue that attaches your muscles to the bone) can get pinched under the bone in your shoulder. A repeated activity, such as heavy lifting,Injury,shoulder trauma, surgery, diabetes, cardiorespiratory disorders, cerebrovascular events, thyroid disease can damage your tendons. Treatments that can help with shoulder pain - pain killers,physiotherapy & if not resolving,may need surgical intervention. In your case , as history pain present since Nov 2012 on & off with increasing severity with history of weight lifting ,kindly see an Orthopedics consultant for complete evaluation. ***Note : NSAIDs (pain killers ) can cause side effects such as diarrhoea, headaches, or dizziness.Taking high doses for a long time can slightly increase your risk of having a heart attack or a stroke,but taking them occasionally for pain shouldn t cause this problem. People who have heart problems shouldn t take diclofenac. If you re taking paracetamol, you need to be careful not to take too much. An overdose can damage your liver. I hope that I have answered your questions fully and been of some help. If you have anymore questions please contact me again anytime Best regards, Dr.Sushma