Your comments history can only be checked for comments made on illustration manga. Access the comments from the link located on my page, under your nickname.
Your viewing history can be checked from the area located on the left side of the top page, under the profile icon.
For content that you have given a “Like!” a smiley icon will be displayed under the viewing history.
In addition, when you become a pixiv Premium member, the following functions for viewing history are unlocked.
- Display even more history of your activities
- Share your history between your personal computer, smartphone, and the official app (iOS and Android)