Problem with my labs hip

My little gyp has developed problems in her hip and I trying to figure out how to cure the problem. I wanna see if yall have very had experienced this before.

Vitals:
*4.5 year old female lab
*English build. 55lbs would be an ideal weight.
*A tad over weight, but far from obese. Weighing in at 58lbs right now.
*Starts limping after exercise and training.
*Developed limp back in Feb
*Very pronounced a few hours after exercise. The harder she runs the more pronounced the limp
*I have given her a few weeks rest - still limps when she runs.
*Its in the right hip - same hip she sleeps and sits on (Yes, I know she has a lazy sit)
*No exercise no limp
*She has been checked twice for dysplasia - Negative
*No pain when I give her hip a hand examination

Have any of yall experienced anything like this? I have been messing with labs/retrievers for years and I'm lost for answers.

It doesn't appear to be terribly painful. Its like it is too stiff or her leg is asleep.

Maybe it is arthritis, but she seems so young for that. Further, she should have the wear and tear on that hip.

I read online where someone suggested a product called Trixslyn for a lab with similar symptoms. Its a bone and joint supplement, but honestly I have no idea if it is snake oil or not.

Any help or suggestions would greatly be appreciated.