MBP Trackpad clicks on its own My MBP start to act weird; the trackpad has a mind of its own. While I am writing this, I have to be in Safe Mode as it let me control more than in when in normal mode, although it has auto zoom the screen. 

In normal mode, the clicks are happening on their own, something lookup, many times dictionary open up, and zoom is happening. 

I had talk to Apple expert on phone, in which he told me about safe mode, and we were able to delete .coms for Mouse and Trackpad. That didn't solve the issue. Apple expert told me to reinstall OS and if that doesn't fix problem, it must be hardware. 

I cannot reinstall the OS as my net is so slow and there is no guarantee if it will solve it.  I have  not dropped my laptop to which I can say it is hardware problem. 

I thought external mouse might help, but that didn't either, same thing happening with a wireless mouse. 

What can the reason and what are my option, as this is my bread and butter.
It very much sounds like a physical hardware issue. For an external mouse to make a difference you must make sure your built-in trackpad gets disabled when the mouse is connected, or the ghost events will keep happening since the trackpad is still active.

Go Prefs > Accessibility > Mouse &amp; Trackpad and make sure "Ignore built-in trackpad when mouse is connected" is selected.