Are you sure it's your LCL? Common things being common, chances are you have soreness of your Iliotibial band (a muscle+tendon which can respond to stretching). You can look up stretches on google. Also, you can try to increase your float by using the appropriate cleat or adjusting your pedal if it's an option, make sure your saddle height is correct, keep your cadence up when it's sore, and stretch twice per day, as well as before and after your rides. These are the measures that really helped me.