what could this be? My ds aged 13

[bluesky]

He has just got in from footie, needed a wee whilst playing, so his tum/bladder hurt, he's just had his wee and now has a horrible pain on his left hand side.

He's in agony, I had to help him up the stairs and into a warm bath, I've given him paracetemol, but he is clutching his side.

If he hadn't had his appendix out 7 years ago, I would be heading in that direction. But can't think what this could be?

[madlentileater]

phone nhs direct. they will want to talk to him as he is old enough.
I've found them v helpful.