equipment recommendation – Is there an easy way to hold a stabilizer?

I recently purchased this stabilizer in order to shoot some video footage:

The stabilizer is easily balanced and I am not using all the counter weights since I shoot with a lightweight mirrorless camera. Yet after using it for a few minutes I feel a pain in my arm so I can not continue holding it steadily.

I have seen many videos in YouTube which demonstrate how to hold and move with it, yet none mentions the fatigue which shortly appears.

I wonder whether it is what it is or if I am doing something wrong. Maybe a gimbal would be more easy to use?

Any tip or personal experience sharing would be appreciated.