If you were injured on the job, workers compensation is normally the only viable claim. If your injury was caused by someone else, not connected with your employment (for example if a UPS driver was rear ended by driver not connected with UPS, you the UPD driver may have a third party claim. That is, the UPS driver may sue the non UPS driver for negligence and damages. If the UPS driver received money from the non UPS driver, then the employer would be entitled to some of the third party money to recoup their loss.
As for your workers compensation case, you should continue to meet with lawyers. If they do not take your case, politely ask why? PTSD and COPD are difficult to prove and costly to pursue.