Year 11 here, I'm not sure if you meant 'history or music' or 'history of music' but btecs normally rely on courseworks which are done in school and in your free time, thus- meaning it will take up revision time for your other subjects. Though it may seem like an easy way out, you still have to do a tremendous amount of coursework to make up for it. If you want to be a lawyer, history is more useful as it builds your argumentative and logical skills but it does mean you will have to learn lots of content just like psychology. Both have their pros and cons, you should choose a subject that is more suited to your studying style.