I Have Had Unprotected Sex 3 Or 4 Times With

I have had unprotected sex 3 or 4 times with the same partner over a 5 week period. I have not been with anyone else at all. I now have redness around my meatus along with a single large red shiny pimple on my shaft and a very itchy scrotum and red slightly bumpy rash on the inner thigh against the scrotum? I am lean and it is not from overweight shading. Are these symptoms all together 1 issue, is it an STD? Any guidance is greatly appreciated