I'm 5'6"

Would like to be at least 5'9"

5'11" would be ideal. Tall but not too tall.

Am I short enough that an endocrinologist could perscribe HGH or something similar?

Are there any stretches I could do or foods I could eat to stimulate the production of HGH?

Get the surgery where they fracture your shins and set them apart a few millimeters.

Sound's appealing. Do tell me more.

Here we are:
http://en.wikipedia.org/wiki/Distraction_osteogenesis

Hang on the monkey bars at recess and get one of your butt buddies to hold on to your feet.

*sigh*

Drink Milk.