For a couple of months now I have had an aching eyeball, it feels almost like the eye is stiff and if I've been reading or looking at something for more than a few minutes then I move my eye in a different direction it aches. Its worse when I first wake up and sometimes it feels like the right eye is taking longer to catch up with the left and makes me feel a little cross eyed. Then for the rest of the day the eye will feel strained/achy. It doesn't happen every day which is why I haven't been to see a doctor or optician but has been bothering me now for 3 days. Could anyone offer any suggestions.

My suggestion is to go see your eye doctor. This could be serious. An Optician can't diagnose you as they are not doctors. Please go see a doctor.

See either an optomotrist or ophthalmologist while symptomatic. This sounds a bit like a scleritis, episcleritis, or some type of iritis. It also may be as simple as presbyopia or hyperopia. It should be an easy diagnosis, however, but you need to be examined.