iPhone 5s touch and typing issues

Has anyone experience or can help me determine how to solve the issue where touching Aps or typing a text results in your iphone losing focus and completing drops what you are doing and takes you back to the Home Screen on your iphone. Fir I.e. When you are typing a text message the displays just disappears on its own. When you click on it to retrieve it. It displays then disappears again. I’ve noticed this lately. Would appreciate any help in figuring out the issue.