Constantly screaming and in pain

My 3 month old has had severe gas issues since birth but we muddled through until about 3 weeks ago when she refused any breastfeeding position except us both lying down.

Then a week ago, she started constantly pulling off. Three days ago she started screaming all the time, intermittent with her pain cry, stiffening her body. Nothing I do comforts her and she cries until she passes out. I'm lucky if I get her to feed for a full minute but she does dreamfeed for 10 mins or more.

She was diagnosed with tongue tie only yesterday (I live in Norway where they don't routinely check for it!!) so that explains some of the fussy eating but not everything else.

I'm sorry for the long post but it is agony to see her like this and I am so worried about her. I feel there is something wrong, and have done since birth, but the doctors here have barely glanced at her because she's so far been putting weight on fine.

Any ideas?