Between 5 to 18 months pld all large breeds have Panosteitis....growing pain....i had it bad . It goes away when we stop growing. Mom controlled my pano by thinning me down...i was a chub..and limiting my protein intake until limping subsides...usually a few days. One thing that made me feel better was lying in hot water with shower hitting my legs.
I had this problem also but grew out of it . It wasn't very nice I'll tell you. I believe I posted it in my diary last year around June I believe. hmmmm, can't remember at this time. But the important thing is I better now.
Oh and I wasn't over weight at all....just growing.