21 year old male. for the last 5-6 months iv kept an eye on a lump just above my left knee, iv notice its growing in size and its causing me quite a lot of pain. but recently iv found another lump, just about my right knee. I used to go to the gym 5 days a week and was quite active, but for the last 2 and a half months iv found it difficult to be able to even stand/walk for long periods of time. I m finding it extremely hard to even sleep, I find the most comfortable way to sleep is on my back, because if I sleep on my side I feel a lot of pain in my lower back and also a lot of pressure in my thigh. would you have any clue in to what it is?