How to get a pharmacy technician job when I'm 15 YEARS OLD?

I would guess most places would require a high school diploma at least. And you are only 15. There are laws about kids under 16 working - what they are - I don't know off-hand. All you can do is keep trying. You ask how to get a job - then you say you are certified and have applied everywhere. That, unfortunately, would be anyone's answer. No one has any magic.

Honestly, it may be against insurance policies to hire anyone under 16 or 18. It may be against store policy to hire anyone under 16 or 18. From a professional POV, leaving your age out, a 4 page letter of interest is ridiculous. With no experience to speak of, your resume should be 1 page and your cover letter one page. If you need to get a job to pay for school, then do what every other teenager does and look at retail/restaurant. The main hurdle is that you can't even drive yet so your reliability will be viewed skeptically until you are at least 16 with a driver's license. You also need to make sure that your premed classes will transfer to your undergrad and that med school will accept them. If your classes are considered AP classes for high school, UCLA will (for example) will not accept them.

Most states require a pharmacy tech to be at least 18, however a few will allow the tech to be 16. None will hire a 15 year old.

How did you get a license without going through a program?? Pharm tech involves many classes and hands on clinicals.