Hi kishan158,
Starting with the concern about your iPhone warming up when charging, it’s good to know that it can be expected for your device to get warm at times. As long as you’re not getting a temperature warning on the screen, this could be normal behavior. These are some examples of when it may get warm:
- Setting up your device the first time
- Restoring from a backup
- Wirelessly charging your device
- Using graphics-intensive or processor-intensive apps, games, or features, including augmented-reality apps
- Streaming high-quality video
You can read more about this here:
If your iPhone, iPad, or iPod touch gets too hot or too cold
As for the battery life, we do see Instagram is using 40% of your iPhone battery. You can turn off the feature that allows apps to refresh in the background to improve battery life. Go to Settings > General > Background App Refresh and select Wi-Fi, Wi-Fi & Cellular Data, or Off to turn off Background App Refresh entirely. See if this has any impact on the issue.
You can also optimize your battery life by turning off Location Services for the app. Turn off in Settings > Privacy > Location Services.
Take a look at the following article for more info on getting the most out of your iPhone battery:
Batteries - Maximizing Performance
Take care.