To solve this problem, we start by recalling the equation of the hyperbola:
\[
9x^2 - 16y^2 = 144.
\]
We can write it in the standard form by dividing through by 144:
\[
\frac{x^2}{16} - \frac{y^2}{9} = 1.
\]
This represents a hyperbola with a horizontal transverse axis. The asymptotes of this hyperbola are given by:
\[
y = \pm \frac{3}{4}x.
\]
The point \((p, q)\) is the intersection of the latus rectum and an asymptote. The equation for the latus rectum of a hyperbola is given by:
\[
y = \pm \frac{b^2}{a}.
\]
Here, \(a^2 = 16\) and \(b^2 = 9\), so the latus rectum equation becomes:
\[
y = \pm \frac{9}{4}.
\]
Thus, the value of \(q = \frac{15}{4}\) when \(p>0\) and \(q>0\).
Hence, the correct answer is \(\boxed{\frac{15}{4}}\).