And there is still discomfort now and then.
also a decreased sex drive that i had been righting off on age but still...
A painless lump or swelling is usually the first sign of testicular cancer. What you describe sounds normal. Your testicles will ascend and descend all the time in response to heat/cold/stimulation. They descended from inside your body through the inguinal canal, just before you were born, and they can move back up. As long as it comes back down, it's not a concern. But since this sounds like something new since your injury, it's a good idea to get it checked out.
The decreased sex drive is not likely due to age (you're 20, not 80 ;-)), but may be due to other concerns. Stress, depression, etc. can all impact your sex drive. How's your relationship in general? Reading between the lines of your post, it sounds like you may have some concerns about your partner, whether his/her weight, or whether the weight during sex is okay, or wishing your partner did something differently during sex, etc. If you want different stimulation, you have to tell your partner. Your partner isn't a mindreader. If his/her weight is too much, say so--in a nice way, of course; remember we all respond better to compliments than criticisms. Next time it happens, you could ask him/her to put less weight on you during sex, or you could even just focus their attention on the positives. You could compliment him/her whenever something feels particularly good, or say something like, "You know, I love it when you do (whatever), or move (however)." People like to know they're doing a good job, and tend to repeat the things that you verbally appreciate :-)