Try clearing the history when you open the browser. If that doesn't work, try going to your phones settings. Press Settings> Battery and Device Care> Memory>Clean Now. This will clear cache and unnecessary functions that are being performed in the background, including your browser etc. If this does not work, check to see if there are any updates needed. Make sure all of your apps are up to date. Also make sure that your phones software a up to date so that they all run smoothly as there can be bug and glitches that need the updates to patch and fix issues. Hopefully this helps.