Could you tell me why my left eye is really blurry and had bad stabbing pain in it?

Needs checking: I pain and a vision change could be a variety of causes. The best and simplest is to see an ophthalmologist and have an intra ocular pressure test to rule out glaucoma. That is a treatable condition that can cause vision loss. They can also see in there is any inflammation, retinal changes and infection present. I would go today.