... I know it's been asked hundreds of times...X-ray arm or not?

[Eve]

....DS (17) for reasons only known to him decided to have a go down some steps on his mates skateboard at college and predictability fell off.

His arm hurts a lot , he has movement in it , but can't twist it or use pressure like pushing. No obvious bruising or swelling.

Worth a trip to minor injuries?

Yes. Ds (aged 8yo at the time) went a week with his wrist "hurting slightly" occasionally.
It was only when he went to play tennis he said it hurt badly, and it was fractured.

There was no bruising and although the doctor said there was swelling, it was only noticeable if you looked very closely.