My IPhone 5c display keeps freezing and having stripped lines or goes black. I must wait a while for it to work again. Any solutions or suggestions?

My IPhone 5c seems to freeze. When this happens there are black lines going either horizontal or vertical. I press the lock screen button and when i do this once more the screen goes to a bright black screen. Occasionally the screen goes completely white and I leave it alone at this point to let it lock itself. Then I press the lock button once more and it seems fine. I've tried taking pictures of the horizontal lines but when I go to check it it's as if the screen was normal. Does any one have an solutions or suggestions? It is greatly appreciated.