Q:Do these have a drawstring?
A:Yes they do. Full elastic waistband. But drawstring also.
Q:Will this work as gym shorts? Will it be good for squats, lunges, yoga?
A:Yes These shorts should work great for a good work out
Q:Do they have a back pocket?
A:No back pocket. It has two front pockets.
Q:Do these shrink a lot after washing?
A:No there is not
Q:is there a front fly?
A:No there is not