Are you under a lot of stress? Lexapro isn't going to take that away unfortunately. And for me, stress often is that heaviness in the head, neck ache, tension. Perhaps also you are not on the right dose of Lexapro. With those meds, finding just the right one and dose can be a bit of trial and error. I also get this kind of head pressure when I'm tired. How's your sleep? Are you getting enough? People your age often need more than they are getting. I'd start to track things like what else is going on, your sleep, what you eat, etc. and then when you call your doctor, you will have that information to add to taking Lexapro to see if it is drug related, dose related or if Lexapro isn't the best choice for you. But I'd say head pressure and such is something I get when stressed out and fatigued too. good luck
How long have you been on the Lexapro? One of the odder common side effects of this med, which I discovered when I took it, is odd pressure in the head. As I went up in dose it made me more anxious because the pressure increased. The gasoline smell I don't know anything about, but sometimes people with head pain smell things. Can't tell you if this part of this is related to the Lexapro, it sounds more like what happens to people after an auto accident whips their head around or after banging the head. Anything like that happen? Here's the thing: if this head thing started only after you started the Lexapro and you haven't had any head trauma at all, then it's the most likely culprit. And if you're taking it and you're constantly panicky, then either the dosage isn't right or it's not working.