Yes you are. Under Massachusetts law, your employer must pay you your usual wages for the first three days of your jury service. Your employer can refuse to pay you for this time only if he can demonstrate that paying you during these three days would cause him financial hardship. After the third day, the Commonwealth will pay $50.00 per day for your jury service.
Although jury service is a big pain in the neck, without your service, Massachusetts personal injury victims, as well as all others in need of a jury trial in Massachusetts, would be out of luck.