E.S.
Such a challenge!
I think your son is likely dealing with a structural problem. This is what I do for work, so I know the signs pretty well. When kids scream like that they are frustrated, and when its for longer periods of time, I find they 've usually been in pain. Which goes along with his increased need to be held and breastfed. if you can find a pediatric chiropractor in your area, Ihighly recommend you give her/him a try. its likely your son might have taken a fall (even little ones can count), or some more subtle torsion in his skeleton might just now be bothering him b/c he may be hitting a growth spurt, and that brings it to the fore. www.icpa4kids.com will take you to the 'find a doctor' link. THese are Docs who've spent extra years learning very subtle, gentle, and specific-to-kids techniques, and will be able to answer your questions about your son's behaviour.
Is it possible he could be suffering from any constipation?
best of luck with this, and if you have any questions, please let me know. ____@____.com