My knee's acting up ... again

I thought I will never experience that pain again ... it started as a slight throbbing pain in the knee on Monday - I must have knocked against something ... Rested at home on Christmas. It was feeling good yesterday. But it's unbearable now ... the level has not reached that of 2 yrs back but it just as bad ... hope it gets better tomorrow ... gotta keep the camera at home ... lighten the load.