Having explained how every pleasure is in fact pain; Patanjali begins to describe the process to end pain,
Heyam: Ought to be destroyed
Anaagatam: Impending, which has not come yet
The pain which is yet to come is worth destroying.
What has happened is past; it cannot be changed. Its effect will shape the present and future. It is pointless fretting over it. What can be changed is what is yet to come. Patanjali directs the sadhak to utilize his/her present to end the pains (which includes all the pains as discussed in previous sutras) that are yet to come through karma under sanidhya of a Guru.
Patanjali identifies the root of pain.
Drashtrishyayoh sanyogo heyahetu
Drashtri: Seer (soul)
Drishya: What is seen (manifest Creation)
Heya: (Pain/dukh) which ought to be destroyed
The cause of pain and suffering is the uniting of Purush (soul) and Prakriti (Physical Creation).
All the pleasures and pains that one experiences in life exist because of a being’s inability to distinguish between real (drashta) and unreal (drishya). The moment a being is able to identify purush as separate from the elements and related experiences, that very moment all pain and suffering ceases to exist and the being is in bliss.