First off, K-pins are like, 30 years old and cost around $.10/each. No one is giving/getting kick-backs for those things. Thanks though, that was funny, made me laugh.
Your doctor is being responsible and acting in your best interest, believe it or not. A big reason he's not handing you fist-fulls of Benzos is the fact that you're 19, not to mention you're already on them (the k-pins). He is most likely cycling through non-addictive/abusable drugs before he gives in and writes you for ativan/xanies/valiums. Get yourself one of those " Pill Books", find the one your taking, and pick out a few of the "side effects". Then after a month of trying the lexapro, repeat your bad "side effects" and ask to try somethiing else w/o suggesting anything by name.
You can walk into any doctors office and make an appointment/ask if they take your insurance. If he suspected you had a drug/alcohol problems, it's probably in your medical records. Any doctor that wants to keep his medical license won't write you a script for anything. If you walk into a doctors office tomorrow saying that you're 19, on k-pins, want a heavy sleep-aid, and have "KDU" (Known Drug User) on your file, the new doc is going to think you are Doctor Shopping.
And Yes, anyone who is prescribed a scheduled drug is subject to drug tests for any/no reason.