Since Meditation is all about energies and when we start to Meditate, we start connecting to higher energies, it is like you are embarking on a new journey and route by train, you come across many new co-passengers, sights, moments and events until you reach your destination,
So why this happen during meditation, it depends on the time and condition also what kind of meditation you are doing.
As we grow we learn, educate ourselves and evolve not to express our feelings and express our feelings, most common one which we tend to restrict or hide is crying and laughing, we stop ourselves from laugh or cry, because we think we are weak if we do the same, so crying is not all about sorrow or being sad, same way laugh is not concerned only with fun, it is expression of many feelings, which with time we forget to express and cover ourselves with layers of life,
Let it flow, emotions are there to flow and is not important, what is important is we are expressing what we have hidden in our heart, and meditation do exactly same, remove the layers and bring closer to self, more we move closer more truth we realize and more human we become,
The beauty of our brain is that it love to protect from moments which might trouble us and create sorrow but emotions are free to flow, meditation is the only practice which let hidden and suppressed emotions flow out of our body and give us feeling of eternal peace, making us focused more on our thoughts and their results,
While meditating, just enjoy whatever is gifted, if you focus your energy on why then you will never be able to enjoy the self and sync, if crying cry, if laughing laugh, be Shiva the expression of the universe, be the Nataraja (the dance of universe) and come close to God,
Stay blessed and enjoy your chant...