No Built-In Speaker

I am running Yosemite 10.10.3 on Late 2013 MacBook Retina 13 inch. Yesterday, suddenly, my earphones made some buzzing sound and then the sound didn't come out, except the buzzing sound. I thought it was my earphone's problem, so I checked with my other earphones, but it was still buzzing. I tried my bluetooth headphone, then it worked. After that, I found out that the sound was muted and I can not change it. Also, the Built-In speaker and microphones disappeared from System Information, and also when I alt+click the volume icon on the top bar. javascript:;