Yes. Child support should not be confused with custody and visitation. Every parent has an obligation to support his or her children. With one narrow exception, no state allows a parent to withhold support because of disputes over visitation. The exception? If the custodial parent disappears for a lengthy period so that no visitation is possible, a few courts have ruled that the noncustodial parent's duty to pay child support may be considered temporarily suspended.
No matter what the circumstances, if you believe that your ex is interfering with your visitation rights, the appropriate remedy is to go back to court to have your rights enforced rather than to stop making support payments.
For help with establishing appropriate child support payments -- while balancing taxes, debts, investments, and many other financial considerations -- see Nolo's Essential Guide to Divorce, by Emily Doskow (Nolo).