A number of things could be making it difficult to turn the steering wheel of your PT Cruiser.
• You may need to add power steering fluid.
• You may need to add air to your tires.
• You may have damage to your CV boots or other mechanical parts in the undercarriage or suspension of your car.
Start at the top of the list.
First: Check and fill your power steering fluid (you may be able to download an owner's manual for your car here: http://www.chrysler.com/en/owners/manuals/)
Next, check and fill your tires to the correct pressure (find more information here: http://caradvice.askpatty.com/ask_patty_/2016/01/keep-your-tires-in-shape-with-proper-inflation.html)
If neither of those improves your steering, then you will need to see a technician to identify any mechanical problems the car may be experiencing.
For additional assistance, please find an AskPatty Certified Repair Shop at http://www.askpatty.com/search/?type=all&m=30&q=&keyword= and they can help you diagnose and repair the problem.