Hello,
1/ Go to Appearance > Widgets and remove the Product Status widget from the shop sidebar. Check the CUP usage after that and let me know about the results.
Could you get information on what requests uses the whole CPU on your site from your hosting provider? They should have some detailed reports.
2/ Go to Settings > Permalinks > check if you use the Post name type http://prntscr.com/s7zqco and re-save permalinks
Regards