workflows run on the user account that is performing the changes to the list/library items.
even if you created the workflow, if userA creates a new item, the workflow will run under UserA,
the only reason you would need to execute the workflow under a service account is to elevate the user permissions, but it doesn't seems you need that
Short Answer: you don't need to make the workflow run under a service account in your case
I think the problem is that you are the only user that can run or start the workflow, if that's the problem we need more feedback about what you are trying to accomplish, but if you are the only user that can run the workflow, then we need first to address that issue.
so a few questions here :
1.- is a site workflow or a list workflow
2.- how/when is the workflow launched