A thought about thoughts

When asked what the greatest commandment was the Lord said to Love the Lord with all your heart, soul, strength and mind. It also says that we are to take every thought captive, it also says the Lord knows our thoughts. Ok so who do our thoughts belong to? Are they ours alone? I mean the Lord knows them but He doesn't put thoughts in our mind. But have you ever had a thought that you were like "dude, where did that come from?" I have. Thoughts that I would never think. So where do those thoughts come from? We are to take every thought captive, which would mean that they are their own and that we are to catch them and hold onto them and make them our own. So who's were they before? Also if we are commanded to love the Lord with all of our mind but we only use 10% how can we do that?
Ok so where is all this coming from? Follow my noodle brain for a moment.
So the other day I was thinking about how it's been said that playing with Ouija can open a door and that it can allow for demon possession. If that's true, then could it also be be plausible that if you go see a movie based on true events of demon possession that it could open the same doors? I'm not saying either way, I'm just thinking "out loud". That got me thinking about how our minds are susceptible to spiritual forces. THEN, I was watching tv and a commercial came on for some Rx medicine. One of the disclaimers said that it could cause suicidal thoughts. That got me thinking about medicine effecting our thougths and how they get there. Whew! with me so far? Probably not but thar's ok. Here's kinda how it all ties together. Lets say an unsaved person goes to see The Last Exorcism  movie. and that some how allows a demon to posses them. (all this is theoretical, but if  its possible think about how great of a tool it would be for Satan, I mean you fill a theater with 50 peopl,e 4 times a day for 3 weeks that's A LOT of people that you are affecting) then they get put on medicine that can make them think suicidal thoughts. Is it the medicine that is putting the thoughts in the persons head? is it the demon? or is it just the person and their own predisposed disposition?
At the very least it should raise eyebrows that there are medicines out there that can put negative thoughts in our head. Shouldn't it? I mean, if people can make a pill that can do that, what other pills can put other kinds of thoughts in our head? And why don't the pills ever put good thoughts in our head?
OK so this post has more questions than an SAT test but this is just what I'm thinking. Maybe it's the Tylenol I took.