Could anyone please offer some advice/info?

Around 8 weeks ago I started getting a heavy feeling in one testicle which is also very swollen. It felt achey much of the time. I went to the gp who suggested an infection and prescribed antibiotics. The symptoms however continued and now the affected testicle feels rock solid plus I have backache, abdominal pain and a persistent cough (i don't know if these are all related to the testicle pain). I went back to the GP late last week and was referred for an ultrasound. I know I should have gone back sooner but kept putting it off in the mindset it would go away. 

I know it might not be testicular cancer but I can't find info on anything else it could be - especially the solid testicle. If this is what's suspected, what are peoples experiences of what happens next and how quickly did things happen? The ultrasound is on Wednesday so not long to wait.

Thanks in advance.