It sounds like you are not able to use the free version of TurboTax. Upgrading to another version of TurboTax is only needed when additional forms are needed to complete your tax return. This might result in additional deductions or credits that result in a higher refund. It is also possible that your retirement income is generating another form that is not supported in the free version.
Please see this link for more guidance on the forms supported in each level of TurboTax.