How will a future pregnancy be affected if i have an umbilical hernia repair? (not sure whether stitches or mesh) but will i have pulling/tugging/pain

No problem: It should not be a problem.

Depend: Pregnancy cause higher intra abdominal pressure for prolonged period which can cause hernia or recurrent hernia. If you have repair without mesh, it can potentially recur. If you have mesh, or usually don't cause much problem during pregnancy.

Usually no problem: Usually the surgeon will repair the umbilical hernia by placing a piece of synthetic, sterile mesh and sometimes closing the fascia overtop of the mesh. This repair is quite strong once healed. So there is a small chance that the hernia could come back during or after pregnancy, but the risk is small if you have healed for several weeks before getting pregnant.