My 5 month old grunts all day long - not associated with a bm. Is this normal?

It depends. Often infants will grunt as they develop speech and control of their voice. Some infants grunt due to underlying problems such as heart or lung problems. You may want to have your doctor evaluate the grunting. You can help your doctor by making a quick video of the grunting, with your phone or camera, and bring it along with you to your doctor's appointment.
Yes. As long as he isn't blue it's normal. Infants make all sort of wierd noises all the time.