Does Lumbrokinase Interfere With D-dimer Levels?

Question: Hello
I have been having pains in my chest that feel like they are originating in the lungs. This has been rather unnerving, and I have wound up at the ER twice over the last 4 weeks due to pains in the chest and a feeling of being short of breath and wheezing. They have been particularly concerned with checking my heart on these occasions, but have also run d-dimer tests which have been negative at 0.3. I have also taken a chest xray (not CT) which was clear. No signs of infection or heart strain. EEG fine. However these pains are continuing. I am particularly concerned about my shortness of breath. Today I ran to the train and nearly passed out with a cramp feeling in my lung. I needed about 15 minutes to recover my normal breathing.
Regarding the nature of the pains: To begin with they were reminiscent of a chest infection, a widespread achy feeling like having run hard in ice cold weather. This was accompanied by feelings of small bursting cramps in the lung/ chest area. I have also had periods of sudden shortness of breath and wheezing without any reason. The middle of my chest has felt heavy and tender, like I have swallowed something sharp and big that has scraped the inside. Along with these symptoms are a sense of pressure up toward my ears and head.
My concern is for pulmonary embolism despite a negative d-dimer. I don't believe that I have any known genetic risk factor, but I am not 100%. I have led a very sedentary lifestyle the last year and have had little or no daily exercise.
This aching and bursting/ cramping pain around my chest is unlike any pains I have felt previously, and I cannot shake the feeling that something is very wrong. However the doctors are hesitant to do a CT scan because they say the risk of radiation far outways the risk of my having an undetected PE.
Any input or alternative theories would be appreciated!
Additional info: I had the seasonal flu shot just before these pains began
I cannot provoke the pains by movement in any way, but the pressure increases somewhat if I bend down. I have had a recurring stabbing pain in one point of my chest during this time, only second in duration but in episodes. I have also felt some pain in this point when breathing deeply and coughing at times.
Additional concern:
Because of my worries about PE I have been taking an enzyme supplement called "Lumbrokinase" lately. Would the use of this type of product have the potential to interfer with the d-dimer levels i.e. cause a lower level that might conceal a clot?

Thank you for your reply. I am quite doubtful that this could be bronchitis since I have no plegm or cough. I have had bronchitis several times in the past, and on those occasions it has taken a very different form from these pains. I have taken a spirometer test, once now a few weeks ago and once in the past. On both occasions it showed results of lung capacity in the lower normal area bordering on slightly obstructed. I am not sure what the PFT involves or if it is similar to the spirometer test. I have been referred to do a exercise ECG shortly. The wheezing is not constant, but comes and goes. I do not smoke, but have smoked in the past (over 10 yrs ago). This pain feels more like bursting, aching cramps than a bronchitis type heaviness. Sorry for my inadequate description abilities.