I just purchased a new home and I have noticed that in my bedroom after I retire and shut the door.. it sounds like someone is trying to open the door but couldn't.. and yesterday when I was finishing up with my shower in the bathroom this time.. the door shook like someone was hurrying to open it as if there was some sort of problem or trouble.. but when I opened the door.. there was no one there.. no one home but me.. has anyone else been through this.. what help can you offer me?

Are you sure this isn't something to do with draughts in your home that you aren't familiar with? Often draughts can rattle doors that are not firmly set when closed.

There can be many explanations, Have you talked to others in your house about it?

I lived in a house in Colorado that was next to a street that had major pipes running under it. The depatment came to fix them but one of the big drainage pipes was so bad, they abandoned it and dug another hole further up the street. They recovered the "dead" pipe but whenever a big enough truck went over, the floor in my front room shook so bad, I couldn't sit still. I jumped up startled so may times I began to listen for larger vehicles and brace myself. When my lease was up, ZING, I got the heck out of there.

Yes as noted there are 100's of physcial reasons, water pipes, air flow in the home, the type of atic ventilation and ground tremmers.

Heck we can throw in UFO's, Bigfoot, and mental illness.
Just being silly on a few of these, but I hope you get an idea, this is of course why anyone who properly investigates any paranomal activity, will spend weeks studying what it is not and most often that is all the find, what it can't be,