Battery running out fast

@omkabra you are really not giving us a lot of information here. All we can start with, is a pretty generic answer.

Make sure that your software is updated and that no apps are running in the background. Assuming that you checked your software/firmware, the next thing to do is to replace your battery. Use this video for that. After that, you do want to go ahead and replace the charging port flex For that use this video

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!