4 month old & sleep(or lack there of) help

So we are at a complete loss over what to do with our son's sleeping issues. His best sleep was at 6-8 weeks when he would have several nights of sleeping from 11-5 or 11-6 w/out waking up (that is swaddled w/ white noise in RnP). Since 8 weeks it has been a disaster. The worst part about it is that it is completely unpredictable. He will v.v. rarely sleep from 9-6 w/out waking up (maybe 1x per 2 weeks). Other nights he gets up 1-2 times (I can handle this), and yet other nights its every 2 hours. We transitioned him to the crib @ 12 weeks (still swaddled w/ white noise). While this hasn't helped the situation even when we try him back in the RnP we still don't get any consistent sleep. I can never tell if he is waking up b/c he is hungry or just plain waking up. Sometimes I feed him (BF) and he eats well 30-40 min, other times he eats for a few minutes and goes back to sleep. Sometimes my DH will go in first if he has just eaten 2 hours ago for example and after 30-40 min of bouncing can get him back to bed, other times he can't. He is clearly tired when he wakes up (not like he wants to be awake and play for example). I don't know what to do. Do we CIO at this point? Start solids (I don't think this will really help). I know there is a so called 4mo sleep regression but this has been going on since 8-9 weeks w/ no break or return to better sleep. Oh and he HATES and fights the swaddle but if it comes off in the night he wakes up, and if we try w/out it or w/ one arm out he doesn't even go 20 minutes. We have tried the following: Shorter naps, longer naps, white noise, swaddle, BFing Q 2 hrs in the evenings, bath before bed, binky/no binky. He is also an EXTREMELY light sleeper (if he hears me roll over in bed across the hall he wakes up). He never had that "sleepy newborn phase either" has always been hight needs/sensitive/reactive etc.
Suggestions?!?!

Re: 4 month old & sleep(or lack there of) help

When DD was that age (maybe a bit younger), she began to break out of her swaddle and wake herself up. Try double swaddling. It helped DD stretch out her sleep.

http://www.youtube.com/watch?v=EOnsKlluHIg

also, try cluster feeding a few hours before he is supposed to go to bed so that he is nice and full.

good luck...it's hard! SOme babies are better sleepers than others