Your employer can fire you for many reasons, but not because you filed an injury claim. If you hire an Attorney, you will potentially get the same benefits as someone who does not hire an Attorney, but your chances are better. It is usually better to have an Attorney. L&I Attorneys usually receive a percentage of your Award (Contingency) in the end. If you do not get a recovery, neither do they. The Attorney Fee must be Reasonable, and must be approved by the Court.
I represent Employers, but I can recommend Worker Attorneys in So Cal if you ask.
I agree with the answer above. It certainly wouldn't be a bad idea to consult with a local attorney who handles L & I benefits. There are many fine attorneys in your area. Also, Washington Law makes it illegal to retaliate against someone for filing an L & I Claim. If you are demoted, have your hours reduced, or are fired because you file a claim, you should definitely contact an attorney right away.
This answer is for general information purposes only and does not form an attorney-client relationship.
You should consult with a competent local workers' compensation attorney for advice on your rights and benefits. As your condition came on gradually, it is called an occupational disease. These can be difficult claims.
Regarding your employment, you cannot be discriminated against by your employer for filing a claim, HOWEVER Washington is an employment-at-will state, which means your employer can terminate you. If you are terminated and feel it is discriminatory, you can file a claim within 90 days of the discriminatory act though the Department of Labor & Industries. An employment law attorney can further advise you.
Since Washington is an At-Will State, your employer can fire you for any reason short of discrimination or retaliation. I have clients who filed an L&I claim who shortly afterward began being treated differently as the workplace atmosphere became hostile. Though this may not happen to you, it would be a smart idea to retain an L&I attorney who can advise you on what steps to take if this happens. L&I is a contingency fee type of practice with your attorney receiving no fee if he/she doesn't obtain benefits for you.