He committed a sin and his conscience is troubling him

No File Exists
Check below answers in case you are looking for other related questions:
He has repented but he cannot restore people’s rights because he is poor
Returning Money Taken Without Permission

No File Exists
Related Answers:
He has recently started to pray regularly
The Sale of a Man Over the Sale of His Brother is Not Allowed
If a person commits a sin for which he deserves to be cursed, can he repent? Is it possible for Allah to forgive him?
He has repented but he cannot restore people’s rights because he is poor
Returning Money Taken Without Permission

Recommended answers for you:
She sees a dry brownish-reddish spot a few days before her period
Listening to music in Ramadaan
It is permissible to sleep on one’s left side
Does touching a dog make one's hand naajis (impure)?
How can he make up for missed prayers?