We practice yoga because on some level, consciously or unconsciously, we know it’s good for us - it’s making our life better in some way. The way it does this is by focusing the mind on a set of tasks, thereby bringing you into the present moment.
(The only problem with that is it can become a drug, and rather than solving our underlying problems it becomes a short-term pain relief.)
The focusing of the mind on postures then invites meditation. The practice itself teaches you how to meditate, by getting you to fully consider your relationship to the movements your making. This teaching enables you to practice meditation in stillness - to witness your relationship to all the things that come up when focusing on stillness. In doing this you begin to notice all the things that are preventing you from being in your natural state of bliss.
Now if you can resolve these disturbances yourself then your mind can allow those things to rest, but if any of the disturbances are beyond your self then at least now you’ve identified them and can seek resolution appropriately.
Yoga helps us feel better because it brings us into the present moment. (And what’s worse, it’s more difficult to recognise that you’ve become an addict!)
Once you’ve spotted your obstacle to bliss, if it’s something that keeps coming up then that is your unconscious inviting you to address it properly and find resolution. This is where hypnotherapy can come in.