Why does only my right eye always feel strained after lasik? 20/20 vision. Feels tender under they upper eyelid. Especially after computer use.

Dry Eyes. Sounds like your eyes are dry, which is not uncommon after lasik. Symptoms tend to worsen with reading and using the computer.
Dry eye. Your description sounds like dry eye. Try frequent artificial tears, warm compresses, fish oil supplements, and ointment at night. If no improvement, see your doctor to consider punctal plugs and/or restasis.
Dry,hyperopia,presby. Dryness is common for a few months. Less common, but still common can be slight overcorrection to hyperopia. If artificial tears relieve symptoms, it was dryness. If reading glasses relieve symptoms, it may be hyperopia or presbyopia. Of course, it can be a combination of the above.
Dry eye after lasik. Dry eye is not always symmetric. With computer use there is decreased frequency of blinking. Patient's often respond well to using artificial tears prior to computer use. Retaine mgd is an excellent artificial tear http://fleye.Com/store/artificial-tears/retaine-mgd.Html other treatments, under the advice of your doctor include omega 3 vitamins, punctal plugs, restasis, and serum tears.
Not fully corrected. You probably have some remaining farsightedness causing problems with near vision. The eye will get sore when it has to over focus. Other possibilities are dry eye, iregular astigmatism or unrelated inflamatory process. You should have an exam with a lasik specialist to determine the cause.