Most muscles run in a compartment...a sack, that is inelastic. It may be that you suffer from a mild 'compartment syndrome' in those two muscles. It's just a wild guess. Long distance runners sometimes develop 'anterior compartment syndrome' of the muscle that causes shin splints, at the front of the tibia. What happens is that, during exercise, the muscles warms and swells, and it isn't always noticed or doesn't always cause problems....until later. When it swells, it cuts off its own blood supply when it wants to swell, but cannot because it has already taken up all the volume outward that the compartment can allow.

Again, it's just a guess. A really good sports physical therapist will know how to help you. Maybe with 'fascial release' methods.