Self-realization happens in the mind. But the body is involved. If the body is creating obstacles to being able to meditate comfortably, then those kinks are in the way and need to be worked out. If there is chronic muscle tension, the mind will be drawn to that tension rather than focusing inward. So, the aspirant needs to release that tension.
Bodily tension is related to emotional tension. Emotions give rise to movement and tension in the body. In addition, strong emotions greatly affect the mind. Have you ever tried to keep the mind still and focused when angry or afraid?
The mind, in such circumstances, jumps here and there and does not stay focused. So, to make progress toward the goal of Yoga, one must work to cultivate peaceful emotional habits.
It’s only with a completely peaceful and joyous mind that one can enter the subtle inner door to the deeper experience of the Self. This is why it’s so important to practice the Yamas and Niyamas and other methods to create pleasant mindedness.
Doing so is an ongoing practice, perhaps a practice for a lifetime. With sincere effort, progress can be made, bringing one closer to the goal of Yoga.