Some scopes have what's called a tight "eye box". The more generous an eye box is the less you'll need to move your eye around to find the center most area of the field of view in the eye box.

Also make sure your diopter is set to your eye correctly, this is your reticle focus. If the reticle isn't in perfect focus then the visual experienced will be compromised.

Sometimes the answer is to spend more $ to get into a superior scope. Cheap scopes kinda suck. I learned my lesson the hard way.