Testicle Injury. Be treated with ease?

I am a 19years old. Around 18months ago i had an injury on the left testicle. I went to a urologist and a gp they said everything was normal but i didnt feel so and also got an ultrasound (not Doppler) which turned out normal, there was a feeling of numbness on the bottom left side of my penis. I noticed that i stopped getting morning boners when i wake up. The sensation on my left side of the penis felt lesser as compared to the right. I used to get erect but it wasn't as strong as before and now with time things have gotten worse i do get semi erect but only with physical touch, i cannot get boners with thoughts at all. It takes time for me to get erect and it goes away quickly. I have been very lazy for the past 3 years aswell i dont go out as much mostly i stay at my home. I think it might be a blood flow issue. Can this be treated with ease? I am really worried thinking about whether this issue will require a surgery. Pls help my exams are coming up and this is troubling me.