I use the Animas Ping, too. (And, love the EZ BG and EZ Carb features)
1) Are you saying you can't pull the inserter out of the inset, just after inserting?
2) Or, are you trying to remove the inset to replace it? Sorry, I just don't want to assume.
IF #1 -- it could be that you've hit some particularly sensitive nerves and may need to just take a deep breath and remove the inset, then insert another one at least an inch away. If you can't remove the inserter, I recommend that you call Animas directly - phone # is one the back of the Ping and the pump.
IF #2 -- is it the surface of the skin that hurts because the adhesive is so strong? Sometimes it does hurt, like a band aid that is stuck on tightly. I simply use my (clean) fingernail to work up the edges where I can then pull it off gently as possible.
OR, is the pain from within or under the skin? Redness? Sometimes, the area gets particularly sensitive and painful due to the body's reaction to the foreign object (the inset) being in there too long, or maybe from inadequate sanitation prior to insertion (germs in the insertion site). Take a deep breath or two, then go ahead and remove the inset, and wipe the area of the hole with alcohol (it will sting, but you'll be okay). If you have difficulty healing or are prone to infections or if it doesn't heal within a day or so, call your doctor's office.
I hope this helps.