Black holes don't automatically have a stronger field than everything else. A black hole the mass of the sun would have the same gravity as the sun, orbits would work roughly the same (barring some neat physical effects), etc. However, unlike the sun it is possible to get extremely close to a black hole, which means the maximum gravity that you can feel in practice becomes much higher.
The gravity just above the surface of the sun is about 270 m/s2 (28 times that of Earth). The gravity just above the surface (well, the event horizon) of a solar-mass black hole is 15212361216813 m/s2.
To answer your last question: if you're orbiting (at a very high speed), you're not actually feeling the gravity. You're floating, just like you'd be if you were in a space station over Earth. This means bones and height and all that will be affected, but only by the lack of gravity, not by the black hole itself. Relativistic and tidal effects might make a difference, but being near a strong source in gravity does not automatically impact your body.