home button randomly doing stuff?

so I've had my iphone 4 for a year and four months as of today and a couple months ago my home button started glitching. it would occasionally work but it also would not at times. it will randomly do voice control and go home and if I press the lock button it screenshots. Now it doesn't work at all when I use it by myself but it will still do the voice control and other stuff randomly. I've recalibrated it many times and reset the whole phone. help?