He's 5 but this has been happening on and off since he was about 3. At first I thought it was related to potty training and was constipation which he was feeling for some reason in his legs instead of his tummy. But now he has no problems with witholding poo and it's still happening.
He will cry and tell me his legs are hurting and he can't sleep. He does seem to genuinely be in pain. Sometimes I give him calpol and this helps him go back to sleep, although now we are abroad and you can't get nice, sugary calpol, you can only get bitter orange horrible tasting medicine - we usually bribe him with sweets if he needs it. I don't really want to give him sweets in the middle of the night so I let him get into bed with me and rub his legs and he usually falls asleep. (If I do the same in his bed he wakes up again later). Actually TBH I used to sometimes give him fruit squash instead of calpol and this "worked" too, as in it calmed him down enough to go back to sleep.
Is this what they call "growing pains" or could it be something else and should I take him to the doctor or is it something he'll just grow out of?