If you didn't alread tried a factory reset, i would do:
System settings/backup&reset/factory reset
You will loose all your personal data.
If issue persist, probably there's a short somewhere in the touchscreen.
Have you noticed if the same behaviour happens with USB connected to your pc?
I suggest you to contact your regional Acer support service.
If i was helpful, a KUDOS is appreciate and remember to mark "Accept as Solution" if you solved your problem.I'm not an Acer employee.