why hasn't medical science found the cure for hiccups yet?

As a chronic hiccuper, once I discovered this technique it all ended. I've tried just about all of them.

Step 1: Fill your lungs to the maximum with air.

Step 2: Plug your nose and close your mouth holding the maximum air in your lungs.

Step 3: Swallow two or three times. The last swallow should be hard to accomplish.

Step 4: Exhale slowly through he mouth, keeping nose plugged.

Step 5: Breath normal hiccup free.