2 weeks in. Couple of questions I can't find answers to online

I had a strange pain in ribs (backside) that went away after day 2. The tremors also reached upper body and I have strong upper body tremors which I enjoy. My upper body thumps and rocks left and right rhythmically and non rhythmically. visually looks like an exorcism. I dont feel anything emotionally yet, but that's not my question

My question is: Tremors stop as soon as I bring my back down on the floor. Keeping the back arched is a strenuous task. In all of the video tutorials I've seen, the practitioners bring their pelvis/back down after 1-2 minutes of arching it. And then keep on tremoring.

I dont carry on tremoring. Therefore I can only tremor for a few seconds before I have to bring my pelvis/back down due to strain. This is not to say my body isnt tremoring. It is strongly tremoring but not when my back is down, unlike how people keep on tremoring

2 weeks ago i posted this question and i was suggested to keep my hips slightly elevated when upper back settles. That position is also hard to maintain because my strongly tremoring upper body brings hips down anyway.

My goal is to be able to do 10 minutes session daily. It's not possible with back arched for 10 minutes. Help