Yes. It can mean two things
1. The bulb is not set correctly into its socket. Twisting the bulb in the socket may fix this.
2. The bulb is going bad and has to be replaced.
1 should be assumed and if resetting the bulb in the socket doesn't work, then replace the bulb.
I should emphasize, if this isn't your job and you don't have a ladder, let someone do it whose job it is. You're fooling with electricity here, which can be dangerous.