(Okay here come the... qualifiers!) - What I'm sharing is based on my conditions and feedback from my Doctors. Therefore, my reply is based on the similarity of our conditions and/or the questions that I've asked or have found answers to. Now... moving on... :)
I continue to take medications for chronic pain (due to various conditions). To address PART I) Q: Is it safe to take Tylenol w/an anti-depressant), A: It would be helpful to know exactly what anti-depressant you are taking so you are able to investigate any type of interactions may exist w/your anti-depressant, then take your question to your doctor for his feedback. For me, my reply is YES, I've been told it is "safe" to take any type of Acetaminophen (only) with other medications, such as anti-depressants.
PART II) "Additional Info" (i.e. Lung Condition). I also, have a similar lung condition - chronic bronchitis (3-nodules in my lungs). I use a generic product called "Mucus Relief", which is Guaifenesin, 400 mg. I take it 3x daily (2x in am, and 1x pm). It helps to break-up, loosen, and expel mucus from my chest. I drink plenty of fluids throughout the day.
Some Extra Info about Me: From my research, I've learned that Fibromyalgia is a "nerve" condition. Whereas the condition you describe above ("muscle and joint pain"), sounds more like PMR (Polymyalgia Rheumatica). Should you be seeing a Rheumatologist, you may want to ask if your bone/joint symptoms have any relationship to PMR.
A Side-Note: I have a team of 5/6 doctors, 2-doctors who oversee all my medications monthly. From my experience, I encourage all to become their own self-patient advocates. This is where one does any of the following: research medical conditions; keep a medical notebook used for all doctor visits; prepare questions prior to doctor appts.; and make notes of any new changes since a last visit. Additionally, retain copies/CDs of test results (all types), to create a detailed medical history; create a written medical overview for you, (doctors, all prescriptions, surgeries, procedures, non-surgical conditions, family med. history, and so forth). I was a caregiver for 3+ yrs. and that period in my life taught me several features/benefits of being an informed patient. Hope you find this feedback helpful. Thanks for putting your question out there.