Please go to your GP. I have a 19 year old son. Since he was about 14 or 15 I have told him how important it is to check his testicles on a regular basis. He has been very good and has checked himself regularly. Two months ago he felt a lump. He didn't tell me as he didn't want to worry me. I made an appointment for him to see his GP while he was at college on his behalf as he told me he had a recurring sore throat, which he gets from time to time. GP felt the same lump. He then got a letter from the hospital which I saw so then he told me. Had to wait a month to go for an Ultrasound examination. Came back all clear. In between the GP seeing him and the ultrasound , he could no longer feel the lump. It hasn't come back, whatever it was, thank God. He had no pain or discomfort, so the fact you feel a lump AND have pain tells me to go and see your GP ASAP.