Do you spend a lot of time in the gym lifting weights?  If you lift weights on a regular basis, you may be abusing your vocal cords.  People who lift weights abruptly squeeze their vocal cords together with a lot of force and then grunt.  This activity, over a period of time, may damage the vocal cords because the slamming together of the cords can cause a callous to build up, changing the mass of the vocal cords.  This may cause a change in pitch and/or create vocal hoarseness.  Extensive weight lifting should be avoided if you depend on a well-functioning voice in your work. Or be sure to ask a personal trainer how to lift weights without abusing the vocal cords.  They may not know the answer so consult with an Ear, Nose or Throat doctor.