Melissa -
I had the same thing (it felt like I was healing all over again), but mine started much later (~7-9 months) and I was told that it was. I was told that it was the scar tissue moving. It went away after a while, and then I got pregnant with my 2nd (due in November) and while I haven't had near as much ligament pain with this one, I have had quite a bit of this 'twinging', especially during the first couple of months.
If it is too painful or lasts for too long, I would be sure to ask your Dr., though - just to be sure.
J.