Emotions are temporary
Emotions come and go; they are temporary. We can define emotions as positive, like love or happiness, or negative, like sadness, pain or anger, but they are all temporary experiences.
We tend to identify our “self” with temporary, ever-changing feelings and thoughts. Yoga, however, teaches us to look beyond this illusion of what we “think” we are.
We are unchangeable
The true home of the soul is beyond time and space, in the eternal now of consciousness. In yoga there is only one problem and one solution. The problem is that we have forgotten who we are and the solution is to remember who we are.
This means remembering that we are unchangeable, that we were never born and will never die, that we are timeless.
You might think, “What do you mean we are not born and will not die - the body dies, right”?
The body dies, indeed, which means the body changes - but we are unchangeable, remember, so that must mean we are not the body.
We are what observes
Thinking changes too, right? So we cannot be thinking, either, because thinking is just something that takes place in us, and we don’t even have to take that personally. What a relief that is! It also means our thinking isn’t able to “get” this. How can something that we are not “get” what we are? So let go a little and feel this information, let it sit with you and see what happens. It means the truth is beyond the thinking mind.
So how do we take refuge in that which doesn't change and remind ourselves that we cannot possibly be the changeable (like emotions, thoughts)?
Become the witness
Becoming the witness does not mean pushing it away; it means allowing it fully, giving it all our attention and awareness but without believing it is what we are. The emotion takes place in us, yes, and you may even say its part of us, but it is not who we truly are, and seeing that frees us to be able to fully experience an emotion—and when we are able to fully experience an emotion it will change, because the nature of life is that sooner or later everything changes.
Feel the raw feeling
When we resist an emotion, it tends to persist. Also, when we believe in an emotion and in the story of why it should be there, we tend to keep fuelling it, and it will linger and come back. But when we can feel the raw feeling, the emotion in the body, without getting involved in any stories about why and how, that is when the emotion loses its grip on us and changes.
This is the highest form of yoga. When you experience an emotion, don't run away from it, don't wallow in it. Just give it space so you can experience the raw feeling of it in the body with no stories, no involvement, just presence! If you can really do that, before you know it the emotion will have changed or dissolved and you may experience the peace that comes from being the pure witness of all experiences.
I hope this will give you a handle on how to deal with emotional pain in your yoga practice.