The voume on my Macbook Pro is really low.

Please make a Genius Appointment and take it in for service. It is in warranty.

vs -

Just to double check, OK?

Have you looked into your System Preferences > Sound? And adjusted the volume to maximum?

Do you have any external speakers attached?

Or an app called "Boom" that you installed?

Is it low on all apps? Is it low on iTunes? If so have you checked the volume bar there?

Excellent!

Which one was it that was causing you your sound problems?

I'm so glad you're all sorted now.