Aiyoo sayang, that sounds really uncomfortable, honestly the skin thinning and tightness around the scar area is quite common after perineal stitches, especially when you're still healing at 3 months postpartum, but since you're having pain with movement and trouble with bowel movements, I'd really suggest checking in with your gynae or doctor to make sure the scar tissue is healing properly and there's no infection or other complications lah. A few of us mums had similar issues and our doctors actually gave us specific physio stretches or sometimes recommended scar massage once fully healed, which made a big difference, but best confirm with your doctor first before trying anything yourself, okay?