If your phone screen lags on the sides before responding, it can be a frustrating issue that hampers usability. Here are some steps you can take to diagnose the problem:

Clean the Screen: Start by cleaning the screen of your phone. Sometimes, dirt, fingerprints, or smudges on the screen can interfere with touch sensitivity and cause lag. Use a microfiber cloth or a screen cleaning solution specifically designed for electronic devices to wipe the screen clean.

Remove Screen Protectors or Cases: If you have a screen protector or a phone case covering your device, temporarily remove them to see if they are causing the lag. Poorly fitted or low-quality screen protectors or cases can create a gap between the screen and the touch sensors, resulting in unresponsiveness or lag. Test the screen without these accessories to check if the lag persists.

Restart Your Phone: Restarting your phone can often resolve temporary software glitches or background processes that may be causing the lag. Power off your device completely, wait for a few seconds, and then power it back on. This simple step can sometimes clear any temporary issues and improve touch responsiveness.

Check for Software Updates: Ensure that your phone's software is up to date. Software updates often include bug fixes, performance improvements, and optimizations that can address issues related to touch responsiveness. Go to your phone's settings, check for system updates, and install any available updates.

Test Touch Sensitivity: Many modern smartphones have built-in touch sensitivity settings. Access the touch settings on your phone and check if there are options to adjust the touch sensitivity level. Try adjusting the sensitivity settings to see if it improves the responsiveness on the sides of the screen.

Perform a Factory Reset: If the lag on the sides of the screen persists, performing a factory reset can help diagnose whether the issue is software-related or not. Before proceeding with a factory reset, make sure to back up all your important data as this process erases all data on your phone and restores it to its original factory settings. Go to your phone's settings, find the reset options, and follow the instructions to perform a factory reset.