I am not an expert, but do you have neck pain at all? If so, C6 (Cervical Spine) is the where the nerve is for your thumb and forefinger. As far as your forearm, it depends on the severity of the nerve pinch. If you lay on your arm with your neck turned a different way, that might be your problem. Try a smaller pillow to get your neck in more of a natural line with the rest of your spine.