In this link, did you run the check your system's ability to run Pro? ArcGIS Pro 1.3 system requirements—ArcGIS Pro | ArcGIS for Desktop
and how do your specs stack up to the minimum requirements?
Are you working on a network? using some laptop? are your data stored locally on your computer or elsewhere?
What operating system? was your computer revitalized before installing? or did you not do a system cleanup?
Any of these could affect performance, so any more details you have would help.