If your iphone screen not responding to touch, there could be different reasons like software glitches, screen damage, water exposure, internal hardware issues. Sometimes a simple restart or software update can fix minor bugs, but if the problem lingers, it might be an indication of display or motherboard damage. Actually, most of the time, the technician suggests replacing the whole screen when the touch functionality stops working properly. Besides, the longer you delay fixing the problem, the worse it might get, so it will be wise to get a proper diagnosis early to avoid higher repair costs later on.