Don't panic, we've spoken to a GP who is fairly confident it's not testicular torsion. He's not in extreme pain, it came on gradually and not suddenly, his testicles look normal and she talked me through how to check the reflex, can't remember the name but you gently pinch part of the thigh and they shrink up a bit. Reflex is normal.
So she's given us an out of hours appt for 4pm. OOH surgery is in the local hospital and she said to bring a bag 'just in case' but I'm struggling to think what it could be that might require a stay. Obviously she's not overly concerned (nor am I tbh, he's behaving mostly normally and the pain comes and goes) or she would have directed us to A&E. But I'm trying to decide whether to call my mum to pick up DD in case I have to stay with DS in hosp. Mum is 2 hours drive away so I need to decide fairly soon.
Anyone else's DS had something similar? He's not injured himself in any way, it literally just started hurting him around dinner time last night. No temp, otherwise well and still his usual chatty self, it's just that occasional 'ooh mum it's hurting again' for a few mins at a time. He says he can't touch the left one because it's painful to touch, and has a bit of a belly ache but quite low down, under the waistband of his pants. I'm from a family of all girls, so testicle issues aren't something my mum or sisters have come across funnily enough 
DH is next to useless, and just said 'no not really normal unless someones kicked him in the nuts'.