Are you happy with how much work you have to do?
What about your colleagues? Are they as busy as you, or do they have really sweet jobs with virtually nothing to do?
Perhaps, more to the point, your colleagues think your job is the easy one?
Measuring workload and allocating work to different jobs can be quite a lot of fun for managers. They don't always get it right, but they usually try hard to achieve something close to a balance.
It is usually the responsibility of managers to allocate work to staff members. Sometimes, they have help from the human resources team, who will assist with writing up job descriptions that include lots of information about what is involved in each job. That's what is usually called work allocation - when a job is assigned a certain number of tasks.
It is not always that easy, however. Work allocation sometimes involves delegation - perhaps the manager gives the responsibility for completing a certain project to a team leader. The team leader won't do all the work that's needed, but will get other team members to do things that contribute to the project. In this case, the team leader has delegated the tasks. Once that happens, you also need to make sure that the delegated tasks are completed, and that can get a bit complicated.
Sometimes, people don't carry out the work that is given to them.
It might be that they don't have time. (This could be a workload issue, which managers should be aware of.)
It could be that they are not sure how to do the work. (This could be a training issue - you can't delegate work successfully if team members are unfamiliar with the processes required to complete it.)
If everything goes well with work, you can achieve the greatest thing ever - job satisfaction!
