Hi denise, Are the "lines" on the glass or on the actual display itself? Either way fixing the broken part, digitizer if it's the glass or lcd if it is the display, will fix your problem. It seems like your device is receiving inputs without your touch because of the damaged part.
Most likely your earpiece speaker needs to be replaced. It's a common problem with a lot of phones. The replacement shouldn't be too difficult and if you don't feel up to doing it yourself most repair shops can do it for you for relatively cheap because replacement speakers are inexpensive.
Hi shunned 95, It is most definitely not the end of your phone. If you have the ability you should open up your phone and check your connectors. They have covers over them but even those covers can come loose and then you have a loose connector. If you don't have that ability I would suggest that you take it into a local repair shop (not a mall kiosk) and have them open it up and try to switch out parts to find the problem.
If the phone doesn't turn on when plugged into the wall then it probably isn't the battery. There are a couple of things you can try though. With iPhones I have had to wait up to 15minutes of them being plugged in before they will turn on especially if they have been dead for a long time. The culprit might be the charging port. Take a pin and clean it out. Sometimes it is just lint from a pocket or dirt that doesn't allow a full connection. If you want to get real crazy, some alcohol on a toothbrush gets it real clean in there. If cleaning doesn't work then you can try swapping out the charging port cable (speaker assembly) for another one in order to fix the problem or rule the charging port out as the culprit. If those don't work let me know an we can go from there.
I have searched high and low and from what I have found, the answer is no. I watch this German guy on YouTube do glass only repairs because I think he is the best, even though I don't understand german. He got the farthest along out of anyone and failed because the glass is too thin and the glue is too strong and something about it being attached to the digitizer differently. I had my step mom (who is german) translate for me.
Check to see if there are any pins (female copper type) missing on connection from the lcd or digitizer. I had a similar problem with an iphone 5C and it was because I lost a few copper pieces from the connection.
If you can still see the image in the background in dim light the inverter may be the problem. If it was me I would probably replace the LCD. You may be right in thinking that the connection may be loose. If it's not the cable then your LCD is slowly dying and it will continue to get worse. Your apple genius isn't much of a genius if all he did was a reinstall.
Sounds like a faulty part. Have you tried putting another screen on it? You might even the putting the old screen back on if the LCD still works on the old one. If another part works then it is a faulty part. If the other part does the same thing then we can look more closely at what might be the problem.