<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hello I m 14 years old and for a couple weeks now I have been having knee pain . A squishy lump appeared right beside my knee cap but is only visible when flexing or bending the knee completely. The pain is very minor o the lump specifically, but my knee itself does hurt. My trainer said I have tendinitis, is that what this lump is caused by?  <response>: Hi, thanks for writing to Chat Doctor. Well, I also agree with your trainer; this kind of symptoms generally relates to spraintears of tendon or ligaments due to strenuous exercises! There could be some loose bodies, synovial fluids or minor injury to patella, muscle or the tendons! I also suggest you to go for an X-ray CT scan microbiologicalcytological test of the secretion for confirmation and to relieve your concerns! Hope this answers your question. If you have additional questions or follow-up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing you good health. 