Hi, did you have Cisplatin chemo as part of your treatment? This could account for the numbness in your feet. The neck dissections could be responsible for the numbness in your face . I couldn't comment on the asthma as there are too many variables such as smoking history, COPD, allergies etc. Are you experiencing dizziness from maybe blood pressure meds, or arrhythmia medications? I would be wanting a full assessment from a physician if this was me.
Maybe Uptown will chime in as he has a lot of experience with post radiation type syndromes.
I wish you well in getting to the bottom of this.
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!