I am a student pilot flying my girlfriends very nice Cherokee 180. I am at about 60 hours and have yet to solo due to a medical clearance issue I'm trying to get resolved. I am a type A personality and my passion is motorcycles. I ride very aggressive and fully understand the risks of the motorcycle especially here in socal. Yet it does not deter me. The reason for my post: I love flying and love learning the technical aspects of flying but have been utterly unable to truly feel comfortable in the airplane. It feels so unnatural to me and every bump or sound freaks me out a bit. I constantly have this feeling that the airplane is going to be my coffin. I haven't learned to trust it. I haven't gotten comfortable with it. My instructor says my flying is spot on. He says I'm clearly ready to solo. He offers me encouragement and says I'm a safe and concienous pilot and that I'll "get used to it over time". Is this a normal feeling with this many hours? It's to a point I'm wondering if I should just give it up.