Is a lump common with Hashimoto's Thyroiditis?

I have Hashimoto's Thyroiditis and within the last six months I have a large lump on the left side between my shoulder blade and neck and now it's very tender to the touch. I went to my primary care physician and she felt is was a tightened muscle and prescribed an anti-inflammatory drug. She also did blood work and recently lowered my dose of thyroid as I was feeling very tired, sluggish, had blurred vision and was hot, with major sweats at night. I did have a full hysterectomy last year and my doctor had me on Yaz, but my primary care physician recently changed me to Permian and lowered the thyroid dose. I'm feeling somewhat better but the lump on the neck is still there. Depending on what I'm doing it gets larger but over the last several days, it has become tender to the touch and has moved to the left side of the neck. So is it a strained muscle or something else? It does feel squishy. I have also had a lot of sores in the back of my head, and they have been there for a month, and it seems as I can't get them to heal. Any information would greatly be appreciated it. Thank you