Feelin the burn!

Oh boy so the bf and I started the P90X work out program. First day shoulders and back and abs. Second day plyometrics (which is baaaaad for my hip flexors....). Today I'm not sure but I'm scared.... I have a problem with the in between stages of standing up or sitting down. If all my weight is on my bum then I'm fine if all my weight is on my feet I'm fine but its that weird in between movement that is KILLING ME. I enjoy working out but having to spend the rest of the day on the couch with the heating pad on my hips isn't worth it. I may find something else to do when plyometrics comes up next time.