There is no enlightenment without suffering. The concepts are so inextricably woven that losing one would render the other obsolete.
Much like Heraclitus’ unity of opposites, the Dukkha/Nirvana twinship can appear contradictory. However, unlike most monotheistic religions which do not necessitate the existence of a perfect evil (Manichaeism and Zoroastrianism notwithstanding), Nirvana cannot exist without Dukkha. This means Dukkha can be considered a gift. It is as powerful as Nirvana. Indeed, Nirvana can’t be attained without Dukkha.
The systems of thought that preceded, and developed alongside and in opposition to, Buddhism, agree in large part on the existence of Dukkha as the residue and fuel for the cycle of Samsara. That suffering (or unhappiness, pain, a lack of well-being, etc.) is unavoidable is taken as a given in Buddhist and other orthodox and unorthodox schools of thought.
The Second Noble Truth is that there is a cause to suffering, and that cause is craving (although aversion and ignorance are also cited as causes). Therefore, suffering is central to Buddhist thought. The entire Buddhist enterprise is done to escape suffering. The Buddha’s Four Noble Truths and Noble Eightfold Path represent a way out of suffering.
Suffering is considered one of the three marks of existence, along with impermanence and non-self.