While we do understand the desire for a pause button, tracking pauses and resumes would require constant monitoring by our servers. This would, in turn, negatively affect our service's performance.
However, tracked Time Entries with similar details are grouped together on our Timer Page, and (if turned on) in our Reports tab as well.
If this isn't the case for you, please make sure "Group similar time entries" is turned on in your profile settings.
The setting for Reports is found in the Global Settings icon at the top right on the Reports' page. 
A consolidated view of similar Time Entries is also available through the Summary Report. Just set Group by to Members / Descriptions.
After the list updates, click on the chevron beside each User name to see the time totals for different activities for that Member.