7wk old keeps waking up straining?

My 7 week old keeps waking up straining, as if he's trying to poo or pass wind. He'll be fine until I put him to bed, then it starts. Sometimes he manages to fall asleep but he will wake up around about every hour and start straining. He looks so uncomfortable, but doesn't cry so I don't think he is in pain? He's obviously tired, he doesn't open his eyes, just keeps drifting back off to sleep then waking up and pushing/straining every minute or so for about 15-30 mins. I just sit there and keep giving him his dummy as it seems to be the best thing to soothe him. Sometimes I'll pick him up and then he'll go back to sleep, so I put him back down but he'll eventually wake up straining again. He's exclusively breastfed and doesn't seem to be constipated as his poos look normal.

Has anyone experienced this or can give me any advise as to what it could be? It seems to be getting worse and is really affecting his sleep (and mine!!)

I feel as though it could be him having trouble with wind passing through his bowels, or even having a sore tummy while his body digests his food. Does anyone know if theres anything I can do to help him if it was either of these things?

Weleda colic powder is very good too, if you need something stronger then try infacol. Give before a feed as a preventative.
20mls of warm water made up of a little bit of boiled water and some cool boiled water can also be very effective.
If it is farts then you can try bicycle legs and pushing his legs up over his tummy.
To avoid the wind going into his intestine you need to burp him and keep him upright for as long as possible after a feed. Some also suggest taking him off the breast every 5mins or so and burp him then putting him back on.
Can I make a suggestion that you invest in a munchkin, they make administering medicines, wind cures and water so much easier. You can get them from most pharmacies and baby stores.