According to this answer Max q for the saturn V is 34kPa. Note that it is very easy to calculate q, as it depends only on velocity and atmospheric density. The aerodynamic stress depends on the shape of the rocket so is more difficult to calculate.
We can get a ball-park figure for the force as follows:
= pressure x area
= 34kPa x (10m)^2 * PI / 4
= 267000 kgf approx or 587000lbf approx.
This is about a tenth of the launch weight of the saturn V.
However it is likely a significant overestimate as the rocket does not stop the air that hits it completely, but rather pushes it out of the way. In order to get the actual drag force acting on the rocket, you have to multiply by the coefficient of drag which is a function of the shape of the vehicle, and is usually somewhat less than 1 (though it can be greater than 1.)
Hope that helps.