I’m On Many Medications For The Treatment Of Metastatic Stage

I’m on many medications for the treatment of metastatic stage 4 liver cancer. I have mucus on my throat, that I can’t swallow down. It’s in my upper throat almost like having a sinus infection and phlegm that won’t loosen. Any over the counter medication that would loosen it? Also, I’ve take Zyrtec and hydroxzine that was prescribed. I don’t think the doctor or pharmacist understood what I told them and put me on allergy medicine