My First Experience - Haunted Stair Well

Allow me to begin by saying thank you for reading my story and for sharing yours. Also, please bear with me as I feel it's important to include the events leading up to my very first paranormal experience.

I live in a condo (a glorified apartment complex) with separate outside entrances. In front of my building is a set of concrete steps that lead to a wooden landing, there you find wooden stairs up to the two units above me and another set down to the two units below. I live on the middle level, right off the wooden landing. I generally smoke on my balcony, but late at night I would go out the front door to avoid waking my boyfriend and/or son (the sliding glass door to the balcony is old, heavy, and loud).

Anyway, one night around 4am I was sitting right outside my door on the steps that lead upstairs. I heard what sounded like a pebble hit the landing above me. I looked around but didn't see anything, so I assumed it was the building settling, finished my cigarette and went inside. Approximately three or four days later, up late again, I went out for my last cigarette before bed. When I was about halfway through I heard another pebble hit a stair above me. This time I actually found a tiny rock on the second stair from the top, and I was certain that it was somehow tossed there.

I was creeped out enough that I went inside and didn't smoke out there for almost 2 months. Then, the last time I went out there alone it was also right around 3:30am, but this time I sat outside on the top concrete step. I was reading face book posts on my phone while I smoked. Suddenly I heard the door knob to my condo turning and I figured my boyfriend or son had woken up, saw I wasn't there and was coming out to look for me. I stood up and looked around the corner, but nobody came out and the knob was no longer making a sound. I looked back at my phone and roughly 10-15 seconds later I heard the knob making noise once again. This time when I looked up I could actually see it rattling and turning back and forth. I waited for the door to open but it didn't. I started to get an eerie feeling because nobody was opening the door but the knob continued to turn. All of a sudden it just stopped, and at the exact same moment I heard two deep, raspy, and labored breaths in my right ear. It sounded as though whoever or whatever was struggling to breathe was just inches away from my ear.

I immediately bolted inside and found both my boyfriend and son sleeping in the living room (just inside the entrance) right where I left them. What makes this even more weird is the fact that neither of my dogs barked. They always bark whenever anyone approaches our door, let alone jiggling the knob like that! I just sat down on the end of the couch, half- frozen. Just when my heart-rate had slowed to under heart attack range, I looked at my door and began to panic again.

Under my door (there's about a 1/2 inch gap where the thick black weather stripping is missing) I saw a shadow of what looked like someone's feet standing there, blocking some of the stair well light shining through. I closed my eyes tight and when I opened them they were gone. I haven't been out there in the middle of the night since.

I was wondering, can't spirits go wherever they want? Because it gave me the impression that it was trying to get in but couldn't. Could the stair well really be haunted? I don't know why but that seems so strange to me.

Also, I didn't really believe in hauntings until about a year ago when I saw a few episodes of Ghost Adventures and began to do some research. Do you think this happened because I now believe? Do you feel like a person who has a paranormal experience is more likely (than those who haven't) to have future experiences?

Thank you so much for reading, I hope it wasn't too lengthy/boring.

Blessings!