Pain in 'da hip flexor

I have searched this topic in vain, maybe someone can help me out here. When deadlifting or squatting, throughout the entire exercise, I have a lot of pain in my hip flexors. I usually stretch them about 3-5 minutes before each workout. Nothing seems to help. The pain is to the point I cant do the exercise at 85% of my max anymore. I have a minimum of 4 days rest before I hit it again. I cant seem to figure it out. I did read that this might have something to do with having short hip flexors…anybody help!