Kendall is nearly 6 months old. On 2 seperate occasions - yesterday and today, after lying on the sofa when he gets off he holds up his left hind leg for a few steps, then goes slightly lame for another few steps before being totally sound again. Yestrady I figured he had stepped on something sharp but woried now as he has done it again today. I can't find any pain anywhere, have moved his leg fully and inspected his pads and nails and can't find anything, and has been 100% apart from on these occasions. Any ideas anyone?