I have noticed a few spots of reddish colour in my semen towards the end of ejaculating (when blotting the tip of the penis with paper) It may be coming from just inside / within the penis although I feel no discomfort from it. I have felt a dull pain from my testicles area recently.

Can someone advice on this?

Thanks.

See your doctor.

Absolutely see your doctor. Not trying to scare you... but this is something that is not normal in anyway. Might be nothing, might be something. Better safe than sorry.