Pursue or not Pursue?

So, without revealing too much about myself.

I've had multiple professionals advise me to take legal action so your input would be appreciated.

Here goes. After multiple years with the same company, zero history of ever being on a Performance Plan, and two months after suffering a heart attack...I was placed on a PIP and four months later- FIRED!!

As a seller, we had a designated sales territory under our "rules of engagement," however, my SM at the time knew this rule wasn't being adhered to and turned a blind eye to these individuals.

Interestingly enough, I was ranked about middle of the team but I was the highest paid Sales Executive on the team and had the most years of service.

I'm a very hard worker and have always been top 20% in sales results for most of my career with this same company. However, this just didn't feel right.

I wouldn't even know what type of law firm to speak with, if any, but I would value your feedback. Much appreciated!