10mo sleep problems, only at night..

Hello, new parent here with a new problem with my 10mo daughter that's really starting to get to me and just can't nip it in bud.. since she was born, my girls always slept really well and putting her down was never much of a chore until about 5 weeks ago when bedtime at night has become a long drawn out battle...She just stopped self settling in bed and now will only calm while in someones arms being rocked. Quite literally, she's asleep with thumb in almost before I have her laying in my arms! As soon as I put her down (or even think about) she's wide awake screaming and just wont put the thumb back in.we're not sure what it is. Some nights she acts like she has reflux, other nights seems just over tired, other nights seem like teething. We took her to the hospital out of desparation one night, 3 doctors and 3 hours later they came up with nothing.The other frustration is that she'll immediately sit up if left crying in bed, so controlled crying methods don't seem to work. she's also a tension increaser, so when left to cry she escalates into hysterics with spluttering and choking so I can't see how that will help. We try sitting with her while in bed and pat or rub her chest, sometimes this works but other times we end up fighting her trying to sit up so then she starts waking up..Is this normal? What can we do to help her get off to sleep without building the bad habit of rocking? What can be done about the constant sitting up?This only happens at night, and usually three hours later she's down around 9-10pm. Her daytime naps are normal and she usually sleeps half an hour to an hour. She is cutting in a tooth right now, but this is 5 weeks going on 6 now. When she's finally down she'll stay asleep til 7-8am in the morning, its just getting her down in the first place without hours of rocking... via /r/Parenting http://ift.tt/2allHHi