Blurry vision, difficulty focusing, high prolactin. are these related?

Possibly: Hormonal changes can certainly affect vision, especially during pregnancy or breast feeding. Usually when the hormones stabilize back to normal, vision returns to baseline.

Prolactinoma: Yes. A large pituitary adenoma secreting prolactin can impinge on the optic nerve. See both an endocrinologist and neuro ophthalmologist immediately.

Possible Pituitary: This triad of symptoms could be due to a pituitary tumor. You need to see an eye doctor for an exam, a visual field and possible neuroimaging.

Many possible causes: First question to ask is "why is the prolactin high?" and "how high is it?" a pituitary tumor can cause high prolactin but so are other things including: hypothyroidism, pregnancy, kidney disease...It would be a good idea to sit down with the doctor who ordered the above test to discuss the next step of workup. You need to systematically work this up.