do sikhs belief in hell and heaven

Respected Hayyrish Raj ji,
Waheguru ji ka Khalsa, Waheguru ji ki Fateh!

In response to your question, the undersigned wants to say that Gurbani totally rejects both heaven and hell. This is what Bhagat Kabir ji is teaching us at Panna 969 of Guru Granth Sahib:-

ਕਵਨੁ ਨਰਕੁ ਕਿਆ ਸੁਰਗੁ ਬਿਚਾਰਾ ਸੰਤਨ ਦੋਊ ਰਾਦੇ ॥ ਹਮ ਕਾਹੂ ਕੀ ਕਾਣਿ ਨ ਕਢਤੇ ਅਪਨੇ ਗੁਰ ਪਰਸਾਦੇ ॥੫॥ (ਪੰਨਾ 969)

Any person, who has come to this world, has two choices. One to follow the route shown by inner voice i.e. Akalpurakh, sitting inside a person as Atma and become a Righteous person (Gurmukh). Second to follow the route shown by mind and become a Manmukh.

According to Sikhism, Gurmukhs are those who follow the teachings of Guru Granth Sahib, get rid of vices, become one with Akalpurakh and Shabad Guru, who are spiritually embodiment of each other, achieve the stage of spiritual equipoise i.e. inner peace and spiritual bliss and finally achieve spiritual emancipation/salvation (enlightenment) in this life itself.

Manmukhs are those, who instead of following teachings of Guru Granth Sahib, follow the guidance of their mind, become Manmukhs, die spiritual death every now and then, waste their valuable life and go away.

Akalpurakh sitting inside each of us (inner voice) , guides us to take the right path in life so as to have inner peace i.e. be in heaven but many of us don’t listen to it. Rather, many take guidance from mind and go on the wrong path and continue to suffer, during the entire life, which you are calling hell.

Hope it helps. If you have any further questions, please do ask. If you find any deficiencies, please point out the same, for improvement in future.

Regards,
Your Brother