Pain while urinating , impotence

Hi, I''m in my early 20s and have been having some on-going problems below the belt.

It all started a little over a year ago after I had unprotected sex with my ex and didn''t bother to wash my penis after intercourse. 3 days later I had bumps on my gland and had a burning sensation when I pee. The bumps however receded and were only apparent when I get a erection. So I went to a STD clinic and had it checked out - told the doc my symptoms and told me I definitely have a UTI but it could also be chlamydia. and he took a urinary sample and swab and some drugs. a week later the results came back and I was clean, so they told me to keep taking the drugs for the UTI and I''d be back to my normal self.
A week later I was still having the urinary pain when I''d pee so I went back and was told it could be prostatitis and that I need to go to an urologist to get it checked out.
So, I did and the urologist checked of the prostate and took another urinary sample. The results came back negative for bacteria. He told me to take some chinese medicine as pain killers and I should be good to go in about a week.
Well, here we are nearly a year later and I still got the burning sensation and on top of that, my gland is soft when I get an erection, the head of my penis hurts during sex sometimes, I can''t get erections as hard and as frequently as I used to, I didn''t used to need physical stimulation to get rock hard and now it won''t get hard without it, I go limp often during sex, I''ve recently started to feel a sensation in my right lower back and lower right side when I ejaculate or get close to ejaculating, the tubes attached to my right testicle seem inflamed and when I pinch it I get the same sensation in my back and side, often after ejaculating my right testicle will get hard while the left one is left small and soft. I also have what looks like a sebaceous cyst in my pubic area which gets swollen/hardens when I ejaculate.

I''m planning on going to the doctor again, but I''d like to get a second opinion. If you have any thoughts as to what it is I could have, or if it''s multiple ailments, etc, please let me know!