I have a pinching feeling in my left eye. Also in the dark feels as though I can't see out of it. What could cause this?

Depends. I am guessing all of this is the left eye only and the right is normal. Nerves around the eye fire occasionally and commonly in the middle years which could explain the pinch. Lowered vision in the dark only (normal during the day?) could be an inherited retinal problem but not likely to be trauma or infection. If persistent, this needs an ophthalmologist to sort it out.