When i swallow saliva, my tongue exerts pressure hard against my palate but the pressure is backwards, pushing the roof of my mouth backwards. normal?

Yes: During normal swallowing, the tongue should touch the palate. It helps to push the food or drink back to the throat. It it bad when the tongue pushes forward against the teeth, called tongue thrust. It may cause the teeth to flare, bite to narrow, space between the biting teeth and puckering to hold the food in mouth. Long term complications are set up.

Consider these...: Difficulty swallowing ("dysphagia") can be distinguished as a "transfer" problem (difficulty moving food from mouth to top of esophagus), "transit" problem (difficulty moving food down the esophagus), "spasm", gerd (due to sphincter problems), or obstructive (webs, rings, strictures, ulcer, tumor), & need to distinguish "globus," LPR. A GI doctor can assess motility &/or need 4 a Speech Therapist.