Is there a mental disorder in which one is unable to determine personal preferences, and as a result, is a cause of great distress?
There is no specific symptom criteria in DSM that matches your description. It’s a very general problem that can be conceptualized in a variety of ways. 

The closest thing I can think of that resembles your description would be generalized anxiety disorder (GAD). Dugas and Ladoceur claims in their research that the main underlying factor causing GAD is intolerance for uncertainty (IU), which - among several things - increases anxiety in decision making. IU paired with another factor for GAD - cognitive avoidance - causes tendencies to avoid difficult decisions completely, or dealing with decisions with excessive worry. 

https://www.ncbi.nlm.nih.gov/m/pubmed/11142548/

Please bear in mind that proper assessment and diagnostic requires a face to face consultation with a licensed specialist.