I feel like i have extra saliva trapped in my cheek?

Thick Saliva: Thick saliva can be caused by dehydration, post nasal drip, allergies, sinusitis, upper respiratory infections, diabetes, hypoglycemia and radiation therapy. Also foods, chemo and medications.

Parotid Gland Stone: Your cheeks contain the largest salivary glands in your body--the parotid glands. If they are swollen with saliva, you may have a sialolith (a stone in the duct that blocks the escape of saliva from the inside cheeks). A dentist or oral surgeon can examine or take an xray of the area to confrim this.