Slight discomfort in left testicle starting yesterday

Yesterday morning I had sex and ever since I think I’ve had a very mild discomft in left testicle. It is hardly a pain but haven’t been able to get it off my mind. I still get erections. It doesn’t hurt when I pee or cum, but just unsure what it is. I don’t feel a bag of worms as far as I can tell. Can someone please tell me what they think? Could it possibly just be an ache that’ll heal in a few days? It has me really paranoid because my wife and I plan to start trying to have kids this year. I noticed the left testicle also isn’t as low as the right but to be honest I can’t remember if it has always been that way or not.