Slight limp - exercise or not?

As some of you know from other threads, Axel has started sleeping upstairs with us. I had to 'help' him up the stairs at first, until he got his own rhythm. He can now do it fine.
A couple of days after he started going up, he seemed to be limping quite bad on the leg with the scar. I felt up and down and checked his pad...no swelling and nothing to indicate why
it'd hurt. He didn't yelp or try and move away.
It only got it's worst when he'd had a mad run around the garden. We rested him for a couple of days and then he had another little run and it got worse. We've rested him again and he's had 2 little walks around the block. Only slight limping.
It's not bothering him, or else I'd have taken him to the vets by now, but if it's still like this early next week I'll take him.
For now though, what's the best to help what I can only assume is a muscle ache....should he be on virtually complete rest like he has been? Or should we be encouraging him on longer walks? Which is most likely to help him?
Thanks in advance
Just to reiterate, it's not a bad limp any more, he's almost normal...just trying to help him back to normal.

I would make him rest until the vet's appointment.

My Lab had something similar: the vet said to stop him going up and down stairs completely and to rest him for a week, just to see if it helped which might indicate it was a soft tissue problem, as opposed to something more serious.

Thanks for the quick reply. Do you mean never going upstairs again? Or until he'd healed?
I guess I'll have to keep him downstairs til then then He loves sleeping upstairs so much, will be hard, but I don't want it any worse.
We've got somewhere we need to be tomorrow, but hardly any walking involved, so should be all right. I'll rest him from walks completely then. I can't get an appointment til Tuesday, Monday morning if I'm lucky!
So hopefully sleeping downstairs and no walks other than his outing tomorrow will help...thanks for your advice!

I meant just keeping him downstairs for now, until the vet has checked his leg out

Phew! I hoped so! We can't take the lack of sleep long term again that comes with him being downstairs, especially now we've had a taste of the good life with him sleeping upstairs
Thanks for your help. I've just got to arrange his vet appointment now. I'm hoping it's nothing serious and he can get back to sleeping upstairs where he wants to soon