7.5 month old arching back when put down

[Giraffeshoes]

My 7.5 month old has just started pulling himself up on to furniture. Since a little while before this started he has been refusing to sit and seems to have become bored with crawling - he just wants to stand (with support) all the time. He has also started dramatically arching his back when I try to put him in his buggy. This is frustrating enough but my real problem is that since a few days ago he has started arching and screaming every time we try to put him in his cot. So if he wakes up in the night (which he does a few times per night - mostly just needing re-settling but usually once per night for BF) it can take over 2 hrs to get him back to sleep due to cycle of crying, picking up, falling asleep, putting down, arching & crying, picking up again (repeat ad infinitum!!)
I am certain he is not in pain and it's not reflux etc (no link to feeding). It's driving me crazy!! Anyone experience this and if so how did you deal with it?

If it's definitely not reflux it could just be him explaining to you non-verbally he doesn't want to lie down or go into his buggy. To which I used to either adopt a cheery am-I-on-drugs? smile and sing or tease mine into submission, talking in an upbeat "Oh so you don't want to go in your cot/buggy, poor old you!" blah blah. Or stroke their tum or blow raspberries on their arms or legs or tummy. Was never too proud to enlist help of family member or friend looking on. Sometimes it works, infuriating as it is when said adult looks smug.