What troubled Hotspur? How did he overcome the problem?

Hotspur believed the change in his life to be a demotion. He soon changed his mind.

Hotspur thought it a great come-down to be a cab-horse, and was disgusted at standing in the rank, but he confessed to me at the end of the week that an easy mouth and a free head made up for a great deal, and after all, the work was not so degrading as having one's head and tail fastened to each other at the saddle.