Back of neck is strained/irritated from poor sleeping position the past while. is it common for this to cause slight blurred vision and scalp burning?

Check pillow height: If too high a pillow, this can cause neck strain, especially when sleeping on the side. Blurred vision could be if tear film evaporates at night with eyes slightly open. Scalp burning usually not related to sleeping position, and should be examined by your pcp. So, you may want to experiment and modify your pillow height, and see if that makes a difference.