Don't tell to nobody that you're working out to not feel that pressure....let the people see but themselves your progress. ....
You could start walking and then run little by little.... yo can do 10 minutes and them tomorrow 15...let your body acostum to the exercise. ...and you will feel great.....
Listen what your mind and body want....and are supplements too over the counter that help with the knee pain..a little expensive but works...that it's what I'm taking for my knee pain!!
Good luck and I hope that you can get the motivation that you need for start