unexplained lump with a constant bruise

I have a lump on my inner thigh, I discovered it about 2 months ago now, it is about 2cm wide, very hard, and at first was quite painful. There is also a bruise constantly on it. My GP first suspected an infected cyst and I was put on a heavy dose of antibiotics, which seemed to help the pain but not the lump. I recently had an ultrascan but the consultant was unable to tell me for sure what it is. He suspected a collection of blood cause by a burst blood vessel, not a cyst, but said he needed to get a second opinion with a specialist. No body seems to be able to give me any specific answers and despite my best efforts, I'm starting to worry. Im 24 and work in a job that involves some heavy lifting and being on my feet for up to 14 hours a day. I have also noticed that about 1/2 cm from the lump the vein is a little swollen. Can anybody give me any sensible suggestions please?