My inner thigh muscles are sore when I use them, feels like post workout soreness but thing is I haven't worked out, I've been real lazy for a week.

Groin Groans. Muscle soreness can come from many things, even inactivity following periods of intense activity. During periods of strenuous use or episodes of use during unusual activity or positions, the muscle fibers can tear and build up products of metabolism that trigger pain even with small movements later on. In most cases gentle massage is effective as well as application of heat. Drink water also.