Why Does My Baby Spit Constantly?

I have a 1month old baby. she spits up constantly and sometimes its just clear. I was told she has acid reflux and is allergic to her formulas. she is on previcid 1/2 pill 2x day. She also take 1.0 ml of bythanecol 4x day. she cries all the time and now she seems to jerk her head left to right and fidgit with her hands and kicks her feet in a jerking motion. sometimes she cries out like I m hurting her when i put clothes on or take them off of her. can you help