I've got a slight pain if I press agaist the end of my penis - it started just after sex yesterday.

I had a look but there are no marks or spots or anything. One thing I did notice is that on the left hand side of my frenulum the skin is quite tight and on the right hand side if I pull the frenulum to the side there is lots of skin tucked in. (I'm uncircumsised) Is this normal and could that be causing the pain?