Little boy bits

[Gargula]

Hi,
For the last couple of weeks my DS (2.5) has been complaining of a sore willy. He often grabs his crotch area and says "hurt there, hurt there".
Took him to docs - no external sign of trouble, managed to get a wee sample (that was fun!) and it is clear, no UTI.
He was circumsised a year ago due to suspected hypospadias. While this was very traumatic at the time he did seem to be completely over it.
So what gives? Anyone out there with little boys who has had a similar issue? Plus does anyone know if having a circumsision will make this area more sensitive in everyday life, even after a year?
Thanks

DS was circumcised at birth. I've not noticed that he has ever suggested that it is sensitive, so I don't think it'll be that.
Is there a rash, or swelling ?
Could it be a hernia and he's not pointing to the exactly right spot?
Worth taking him back to the GP if he says it on more than 1 day.