NTI guard for jaw pain. It hurts. Pain?

My dentist gave me NTI guard for a week or two for diagnostic purpose. My symptoms are, Constant pain in lower jaw under ear and neck for more than 10 months. Also tapping and biting pressure on 46 since this started. Suspect root fracture in 46. Had cbct. Nothing found. Endo told to do root canal for tapping and biting pressure. No cavities or infection. Had Rct &crown. No changes. Constant pain in the lower jaw under ear and neck along with tapping and biting pressure on 46.OMFS(tmj) said it's Myofascial pain dysfunction but not sure about 46. So went to another dentist. He said to do nerve block and NTI as part of diagnostic test. Nerve block on 46 takes away the biting pressure pain but not the lower jaw pain under ear. What does it indicate if nerve injection on 46 take away biting pressure pain?I got NTI to try for a week or 2to see if it helps. It's very bulky and uncomfortable to use. I used it for a night and my lower jaw infront of ear area hurts a lot. Never tried any guard.