iPhone screen is unresponsive and closes and open apps by itself

So I have dropped by iphone 5 in the past before, but about a month ago I dropped it and cracked the screen but got it fixed, again a month later I dropped it and the screen once again broke and shortly after, for a few hours, the screen was unresponsive but after that it worked. Now, three days later, I dropped it yet again (i know, i know, just don't judge please lol) but this time the screen is completely unresponsive, but at times when it does work and i log into the phone, apps close and open by themselves and the phone starts randomly typing by itself and so on. though the home button works so i have been texting through the use of Siri but even that glitches sometimes. Also, my lock key has been broken for quite a while. I'm wondering what I can do to fix this problem. P.S. I can't take it to the Apple Store because i don't have warranty for it. Could this also be a hardware problem? Im not sure. PLEASE HELP.