<s>[INST] I have a moving lump under the skin on my knee and when touched it is very painful. I am a 60 year old housewife. over weight have had surgery about three times scoping. this just developed this year and at night the leg throbs like a tooth ache and I do not know where to put it..when I wear blue jeans and the knee bends the pressing of the pants hurts it. [/INST] Hi, Dear,Thanks for your query to Chat Doctor. Studied your query in full depth of its details. Reviewed it in context of your health concerns. Based On the facts, You seem to suffer from-Synovitis with Osteoarthritis due to old age changes in the knee joint and due to long-standing obesity you have. Compression effect on the knee movements increases the severity of the knee pains you have due to arthritis. Other causes-could be bursitis of the knee joint/or any other knee tissue tumor. Other causes need to be ruled out by Second Opinion and physical examination from Orthopedic Surgeon.USG and CT knee would fix the causes of such a lump. Hope this reply would satisfy you and would help you to plan further treatment with your doctor there. Welcome any further query in this regard, which would be replied in next session. Good Day!! Chat Doctor. N. Senior Surgical Specialist. S. Genl-CVTS </s>