Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.
It does sound like something mechanical. It may be mucus or bleeding /bruising from the clots or small areas of your lungs sticking together a bit. It sounds like you are doing the right stuff. I would suggest trying the things I mentioned in #1 and #2 here https://www.dailystrength.org/group/pulmonary-embolism/discussion/any-tips-or-help
#1 will help you clear any mucus and prevent it from turning into something nastier, and #2 will help reinflate any areas of your lungs that are sticking together.
Good luck!
Anyhow, I started to feel this raspyness and had a cough when I would get up too. This was before I knew I had a PE. I asthmatic as well and pregnancy made my asthma absolutely horrible.. So I too chopped this up to just asthma. Or a bit of bronchitus since I am Canadian and my lungs kill me around now.
When I was diagnosed with PE they said I had pnuemonia from prior to all this.. so I would suggest if it persists to get it checked. They needed to give me quite the antibiotic.