After being on Levo for 21 years, I purchased some T3 and started taking 50mcg of Levo and 6.25mcg T3 (Tiramel). Have noticed a tightness in my chest recently and feels like I can't take a proper breath. I suffer from anxiety/panic attacks but this is not that. Nhs endo took me off Tiramel and started me on liothyronine T3 a couple of days ago with 75mcg of Levo. The energy I was starting to get back is going and my anxiety is feeling bad again. Tightness in chest and breathing still very noticeable and uncomfortable. I was diagnosed with prolapsed heart valve 20 years ago and had ventricular tachycardia. I understand this is common with hashimotos. Not sure if this chest tightness is linked with meds of heart? Anyone else have this?