Painful Lump On Thigh , Help

I have had a soft large mass ( approx 5" long, 4" wide) on my upper left thigh for about 18 months, when I first discovered it, it was quite painful and discoloured but not like a bruise, it seemed very veiny.
I had not banged or injured myself, it just seemed to appear.
I went to doctor who after first saying that I must have one fat thigh (i weigh around 130 pounds) eventually sent me for a m.R.I scan.
The results came back and showed up as a large white growth that the specialist said was a tumour, I was asked to go back 2 weeks later and when I did he said it wasn't a tumour after all, just an 'odema'
i never heard anything again untill I recently went back to doctors regarding something else and they asked me about it.
It is still there but only painful to the touch or when I am cold my leg aches in that area.
They have referred me back to another hospital and I am now waiting for another appointment.
The thing is because of the last experience I am wary of believing what they are going to say this time.
The other worry I now have is that for about a month I have had severe back and shoulder pain, and some discomfort swallowing food.
The doctor has said it could be an infection in my esophagus or a more concerningly a cancer of the gullet, he has done blood tests which I am now waiting for results. He does think cancer is unlikely though as I am only 35 and not in the age bracket common for this type.

I am worried sick that the lump is a malignant tumour which has been ignored and now this possible esophagus problem is a secondary cancer.
Any advice would be a great help.