Joined a while back to learn a few things and have a short story with many questions.

I started having some aching in my left testicle and left groin/lower stomach area. Kind of felt like I was kicked in the nuts yesterday(but wasn't). Thought it may be the new boxer briefs.

Did a self exam and found a lump on the side of my left testicle. Doesn't hurt, but is definetly hard. Aches a bit after an self exam.

I do not have any insurance.
So I managed to find someone to do blood work. What should I test for(HcG & AFP)?
I also found a sonogram place that will do the work for about 100USD. Are the tests a real specialist job? Are they completely trustworthy or would I still have to have to get XRays etc.?

If I were to secure insurance after running any of these test anonymously would it be a pre-existing condition? In that vein is there any cost information available?

I have learned a lot already from all the stories and information on this site! I am very glad there is somewhere to look. Thank you again for any help you can provide.