Fullness in ear and decreased hearing, slight tinnitus. Due to my grinding on that side?

See an ENT ASAP. There are a few things that can cause the symptoms you are noticing, including TMJ disorder or cranio-mandibular disorders. Tinnitus, ear fullness and decreased hearing can also be symptoms of serious ear problems such as otosclerosis, meniere's disease and acoustic neuroma. I recommend you see an ENT for evaluation before writing it off as jaw, or TMJ related.