Any person involved in a rear shunt is probably going to have suffered some kind of whiplash, even if they did not feel the need to make a claim previously.
Irrespective of whether you did, or did not, make a claim previously, and again, irrespective of whether you were successful or not on that occasion, makes no difference.
You are in fact entitled to make a claim for damages for the personal injury you have suffered from this second accident as the fact that you have had a whiplash injury before does not preclude you from claiming.
You need to be aware however that it may affect the amount of compensation you may receive. It s for this reason that you should always get yourself checked out by your doctor or your local Accident and Emergency Department following an accident where there is suspicion of an injury. It is also a prerequisite that you inform the police of any accident involving personal injury.
Most motor insurers now offer legal protection as an add-on to their policies, so get in touch with your insurer and submit your claim. Failing that, there are many legal advisors offering no win, no fee services.