C-section incisions are quite long, as you know. Is your pain along the entire incision, or just in one spot? The reason I ask is because I remember the stitches working their way out in various spots long after I thought I was healed. They use dissolving stitches internally even if you had staples externally, and sometimes they don't dissolve, and your body can either build up around it, or work it out, causing swelling and some pain. Something worth looking into. Definitely see you surgeon though...sometimes er docs aren't prepared to handle OB issues.
Oh, I've had 3 c-sections and even though my last one was 18 months ago I still have some pain from the incisions.