This is probably best answered by a Urologist.

I'm a 29 year old caucasian Male, 5'9 160 lbs, no history of cancer in my family.

About 2 weeks ago I had a sudden large decrease is semen volume while masturbating, no initial "blast" upon climax, just kind of dribbles out. The contractions feel as strong as ever but the volume is not even half of what it was before, this happened literally overnight, one night I was fine, the next day I noticed this. There is no pain associated with this and my urination seems normal.

I stopped masturbating for a week to see if it would have any effect and it didn't seem to help, now this week I'm noticing a swelling feeling in my left lower quadrant of my abdomen. I can't feel any bumps or swelling with my hands when I feel around that area but I can definitely feel some kind of swelling sensation inside of me. I assume these are related as they came about just a week apart. Theres not really any pain in the area of swelling unless I sit in such a way to put lots of pressure on that area

I'm in the process of looking for a GP as I type this, I currently do not have one though.

Any ideas?