The thing I am most worry about is that the weird feeling in my eye is cause by something growing in the middle layer/outside of the eye, like a tumor or something like that. Am I worrying too much, or is it really a possibility?
I would concentrate the workup on the flashes of light that could possibly be explained by a posterior vitreous detachment, retinal detachment, vitritis or pars planitis among other things. If these things are not seen, then it may not be able to be explained but you would have the peace of mind that there were no serious eye diseases. Regarding the weird feeling - I don't really have much to offer than to make sure your eyes are healthy and take what you have. Look for the good in all of this - that is that hopefully you have healthy eyes without an eye disease like macular degeneration, glaucoma, diabetic retinopathy, etc.
MJK MD