Generally this sensation indicates entrapped or pinched nerve. Which can be anywhere from the arm, shoulder or neck area. If there is any discoloration to the skin, it could also indicate a lack of blood circulation. You need to let your doctor know. Generally a NCV and/or EMG test can indicate where this is occurring for proper treatment. However, it's now known if it's safe to do these test during pregnancy. Your doctor may have you hold out until the baby is born, but you do need to let her/him know.
Congrats by the way on the baby. Hope this helps, If you need anything else please feel free to ask. If you found this helpful don't forget to click the *ACCEPT* button and leave *POSITIVE* feedback.