The first thing I usually do is check the paw of the leg he is limping on. It is usually something he steeped on that has to be removed.
If that’s not the problem, try to feel where the pain is coming from. See if she cries when you check the joints, feel for inflammation.
If these are not the case then you have two choices.
Wait a day and see if it goes away or get her to a vet(the preferred choice)