Have you read the No Cry Sleep Solution? I haven't read it but it is supposed to be really good...maybe someone else can shed some light on what it's all about? Do you have a sling you can put him in to get him to sleep? Will save your arms a bit and decrease the stress on your back (because his weight will be distributed fairly evenly over your body). Hope he gets better for you soon...DD has wanted to be rocked to sleep a lot lately for her day sleeps so I can imagine how much of a PITA it is everyday!
Would he sleep in his pram?

(ETA: yes I had to keep my tradition going of replying to all your threads )