7mo constipated and SCREAMING

Hey everyone. My son will be 7 months old on Thursday and has recently taken to screaming. Not yelling, SCREAMING when he's tired. He will fight me tooth and nail to go to sleep. He's also constipated and every time he tries to poop, he SCREAMS. I don't know if the two are related. He used to go 3 times a day until we introduced solids, then he slowed down to once every 3 days (with no discomfort.) But we're on day 6 of no poopies right now.

I've tried everything. I have to essentially wait for him to pass out to get him to sleep and nothing is helping him poop. Bicycle legs, tummy massage, water, gripe water, gas drops, prunes, rectal stimulation... Nothing is working. I hate to see him so miserable and I feel so helpless, but I'm also at my wit's end. I've had to just set him down and walk away for a minute a few times because he's shrieking in my face for hours and I just feel like I'm going to bawl.

Mamas, what should I do? I've been told the pediatrician won't consider it constipation since he's breastfed and if hasn't been over a week and will just give him a suppository, but at this point I don't know what else to do. Is the reason he's having a hard time sleeping because he's constipated?