To dream that you are being injected for health reasons, suggests your need for healing behavior/ideas/attitudes. You need to develop yourself on a mental and spiritual level.

To dream that someone is forcibly injecting you, represents your negative attitudes about a particular situation/person.

It also indicates the influence of peer pressure working against you. You are recognizing that someone is forcing their negative and unwelcome views/values on you.

See also: Syringe.