<s>[INST] My right knee starting to hurt this eve, it felt like my interior ligament was "rolling" over something & it hurt quite a bit. Then, after icing it, I felt a small pea size limp that I could manipulate to move it around. Any ideas? I didn't doing anything out of ordinary today , but I do have osteo arthritis and Lupus. [/INST] Hi...The interior ligament rolling inside your knee could be a tendon rolling over the bone. This is possible because your muscle tightness can tighten up the tendon rubbing onto the underlying bone... The spea sized ball what you feel is the inflammed tendon...I recommend you to..Continue icing frequently...5-6 times in a day on the  pea sized lump area and area on the front of the thigh..keep it compressed with compression bandage...If you have a analgesic gel/ointment apply it on painful area...Gently knead on the muscles above the knee...Gently stretch the front thigh...back thigh...inner thigh and outer thigh muscles...Once pain gets relieved then start rehabilitation for your knee...keeping a rolled towel under your knee and pressing...Exercises like Bridging...leg extension...leg curls..calf raises helps to maintain strength around knee joint...and gentle stretch helps you to maintain your knee pain-free...Hope this is helpful for you...Kindly revert back in case you need any further information regarding this.... </s>