I am in a similar situation. I took medical front office course and am now working in a front desk role. I would also like to take medical assisting and phlebotomy as well. Boston Reed college offers the MA program at various locations in San Diego county as well as CA. The classes are typically all day Saturday, which is great if you already work. I also plan to intern at my company. Their program is about 4-5 months long. There is also a company called US Colleges that offers MA training on a flexible schedule. They have a San Diego location. I don't know of any online programs. I think because you need a lot of hands on clinical training, which would be hard to do online. Hope this helps.