<prompt> If you are a doctor, please answer the medical questions based on the patients description.I have had a knot on my right side at the top of my ribcage for years. This morning when I woke up, the knot and the area around it are sore. No physical activity yesterday that could have caused a muscle injury. The area is warm to the touch but not hot. It dully aches unless touched and then it feels like pain from a bruise. It seems swollen but the swelling is not visible. I had the knot looked at about five years ago and ultrasound doctor said it was nothing. The position is more towards the back versus being close to my breast. I m 30. And my menstrual cycle ended 3 days ago. The knot is mobile and I am able to move it between my fingers. It doesn t seem any larger than it was five years ago. It is hard but not like a bone or marble.  <response>: Hi! Thanks for writing to Chat Doctor sharing your health problem! In short, swelling means collection, pain means infectionirritation and mobile means benign... Therefore, your lump on the rib cage is not a thing for worries but still it should be cured because of possible complications like infection, severe pain and morbidity. I must recommend a needle biopsy first to confirm the nature of the lump and as per my experience, it could be:1. Lipomaneurofibroma like benign skin lesions2. Inclusion cyst like sebaceous cyst3. Lymph node enlarged due to local infection even tuberculosis etc.4. Ectopic breast tissuetumor like fibroadenoma or fibrotic disease Hope you got the answer; please revert to us if any more clarification IR required! Wishing you good health. 