I'm confused like the chicken and the egg! I've got chest wall pain and some minor shortness of breath (but very annoying and uncomfortable). Not sure if the chest wall pain can cause some breathing problems. OR, is the Mucinex (guai) making the chest wall pain worse. I only took 1/2 of a 600mg tablet. Doctors say I don't have true asthma, but I do get mucus in the bronchial tubes (reactive airways due to irritants). I think this makes me feel SOB and having a tough time trying to cough up the "junk." I'm only Alvesco inhaler, Singulair and Nasacort AQ for this problem (have been on these meds for quite a while) and was doing OK. Also Xopenex as needed. Now, the last couple weeks I'm having this breathing problem again and chest wall pain. So, again I'm wondering if the chest wall pain and give you the impression of SOB. Anyone else relate? What do you do to treat this? Even looking for natural remedies.