Clergy and missionaries always pay social security (self-employment tax) unless they have an approved religious exemption form.
As you are a common law employee, you receive a W-2. But clergy are considered self-employed for certain tax purposes and pay self-employment tax (15.3%, the employee and employer share of social security and medicare).
In Turbotax, enter your W-2 as-is, then on the page for special circumstances, check the box for "religious wages". You will be asked if you have a housing allowance, and the program will generate a schedule SE to assess self-employment tax.
If you have work-related expenses, they can be deducted twice. Once from your income subject to income tax, using form 2106 as an itemized deduction subject to the 2% rule using the normal employee unreimbursed expense section. You can also subtract your expenses from your income subject to SE tax but this requires a manual adjustment that has to be made in the desktop program and can't be made online, and you have to attach a written explanation and mail your tax return instead of e-filing. Ask for more info if you want to do that.
You will also want to read this.
http://www.ecfa.org/PDF/2016-Preparing-Tax-Returns-For-Clergy.pdf
