Hi Dear, Welcome to HCM. Understanding your concern. Thanks for your query . The stiffness of tongue along with restricted movement is always a cause of concern . In your case the most probable reason for stiffness of tongue and restricted movement id radiation therapy. When person is undergoing radiation therapy it causes dryness of mouth as a side effect which further causes stiffness of tongue . This dryness and the anemic condition as you mention in qery further make the tongue pron to infection . I would suggest you to consult your radiologist and oral pathologist for proper evaluation of the condition and rule out causes like oral thrush ans any malignancy . Doctor may take small tissue of tongue for biopsy biopsy . Doctor may alter the radiation dose , prescribe iron supplements , prescribe saliva substitute and recommend certain tongue exercise . Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari