Thank you for your question. This usually happens because of a fear that without pronouncing the Arabic letters correctly the prayer will not be vaild. But when that fear is out of balance this can lead to someone over pronouncing the letters or repeating many times. The way to get over this is to not think about it so much and to ignore the urge to keep repeating. Get your pronunciation checked by someone and then don’t worry about repeating.
As for being distracted that is normal and there are things you can do to help such as praying in a quite place and turning off your phone.
May you always be successful