Sakit lepas bersalin tu sangat normal, mama! Biasanya it's because the area still healing, ada inflammation, or kalau breastfeeding the hormones affect lubrication jugak. A few of my mum friends had the same experience, some lasted a few weeks, some few months, tapi it did go away. Since you're saying it's just 4 seconds of sharp pain, that's actually a good sign it's improving already, but do mention it to your doctor or gynae just to make sure there's no tear or infection, okay? They can check and give you peace of mind, then you relax more, which actually helps dengan the pain too.