Red vein going up penis

Hi

I have a red veing going from the top of my foreskin at the back of my penis in the middle going to the bottom of the penis but it widens out and fades towards the bottom. My penis is sore mainly when I need to wee but it doesn't hurt to wee.

I do masturbate a lot - could this be a cause and what should I do?

t is slowly getting less sore and painful but there is still redness.

Please advise

Thanks