  We study Homogeneously Precessing Domain (HPD) in superfluid $^3$He-B in a
regular continuous-wave nuclear magnetic resonance (CW NMR) experiment. Using
Fourier analysis of CW NMR time traces, we identify several oscillation modes
with frequency monotonically increasing with the frequency shift of the HPD.
Some of these modes are localized near the cell walls, while others are
localized in bulk liquid and can be interpreted as oscillations of
$\vartheta$-solitons. We also observe chaotic motion of the HPD in a certain
range of temperatures and frequency shifts.
