All Balochistan states joined Pakistan by their choice in 1948. Tujh mein dam hai tou aa kar ukhar lay. Chittagong did not join Bangladesh by choice, they became part of Bangladesh because they were part of E Pakistan. Only refrendum in Chittgong.
There is no rebellion in Chittagong region and so no need to hold a referendum as it will be a waste of time. You realise that majority of people in Chittagong region are ethnic Bengali Muslims?
Balochistan? Irrelevant if they decided to join Pakistan by choice in 1948. Is Pakistan scared that they will vote to leave if a referendum was held now?