I think it sounds like vasospasm too. I don't know much about it, but I've heard about it here on BB. Try putting a warm face washer on your nipple just befor you attatch.

I tried that once & it worked miracles! No pain with attatchment at all. I stopped feeding my first 2 & struggled with my third & I now think vasospasm is why. Although I can't be too sure. I need to do some research before I start feeding this bub.

He might be having a growth spurt & thats why he's so unsettled at the moment. It is common for a new baby to breast feed every 2 hours during the day & they often cluster feed early in the evening, then will sometimes sleep very well at night. These feed times can be all over the place though, with the longer sleep is during the day.

Every baby is different, so keep to his lead with the feeding times. 5 - 6 hours between feeds is fine maybe once a day, but I'd be offering to him every 2 - 3 hours, as that sounds like too long between all feeds to me.
Try getting in touch with a LC & the ABA & see how you go. Good luck.