Not to be argumentative (really ), but that's borderline nonsensical; you're comparing a profession to a broad category of educational attainment. Teachers typically have a degree in the humanities. What other profession is so commonly viewed as underpaid?
Sure -- though that's almost just two ways of describing the same thing. If teachers were paid $500k, few would describe them as overworked, and if they only had to work 4-hour days (with current salaries and benefits), they might be fairly compensated.
Compared to what? In the US, teachers are absolutely underpaid relative to their similarly-educated and -skilled peers in other professions.