Pen tool for audio not working

[Kayla5C41]

I'm not Premiere expert, but I've been using it for quite some time now for basic editing. Thinking back to past projects, I remember always being able to use the pen tool and click on a portion of adio that would put little markers or key frames on it to adjust the aduio up and down. Now no matter what I try or what I google, I can't seem to get that to happen again. And yes I have the most updated version. Any help would be appreciated  

[RobShultz]

Please make sure that the clip is highlighted and that the channel/volume stop watches are turned on  (blue) in the Effect Controls panel.

[Ann Bens]

[Phillip Harvey]

Firstly, make sure that you've got enough vertical space to reveal the keyframe envelop to work on: 

If you don't see the keyframe envelop (the line going across the audio that you would use the pen tool on) make sure that you have keyframes turned on for clips in the timeline:

 

Ann beat me to it