Gymnastics tips fast?

I'm 13 an I just started gymnastics ( ik I'm a little old to strt but Idc) I had my second practice yesterday and this morning when I woke up my neck hurt badly! I could barely move it at all now though when I look up it's fine but when I look down it hurts really bad so I can't even really look all the way down plus my shoulders are sore and for some reason under my cheek I think part of my jaw hurts really bad on ly when I touch it though any is it from gymnastics and tips how to make it better and any tips on gymnastics (stretches wht to practice) thanks!