Duloxetine is a good medication for symptoms of somatization. Generally it's well tolerated with fewer adverse effects. But it can cause similar problems as Venlafaxine although with less frequency. Best way is to start at low dose and increase gradually. Further accurate advice will require more specifics of the case. Discuss with your Psychiatrist about your concern and he/she should be able to handle you queries.

Although both belong to the SNRI class of medication, there is marked differences in the side effect profile. Clinically, Duloxetine tends to be better tolerated than venlafaxine. Start the med, keep a watch n refer to your Psychiatrist if you experience any distressing side effect.

Not necessarily but since it belongs to same class, you may experience them.