Taking the person at their word (I hate snotty b1tchy people online who think they know all about a person based on a post on the internet)...You must have just done something recently to put a strain on it, there is no way symptoms would take that long to appear.
Slow growing cancers work faster than that let alone muscle damage.
The first report being 2 years later may mean that any judge would say they were unrelated, and the insurance would have medical experts to testify so.
I doubt you'd have anywhere to go with that.
If it is indeed that someone said "you mean you didn't claim?", then either consciously or subconsciously you decided on some level to start feeling pain, IMO just let it go it's too much time gone by.
On the wider issue of claims.
Irelands justice system is a disgrace in a number of ways, the excess suspended sentences, clear and obvious murders charged as manslaughter, the lack of a habitual offenders law so you can rack up 20+ convictions and still keep going...but the claims culture is among the worst parts.
Nothing except pure willful negligence or at the very least incompetence and sloth should = compensation, and I've never understood how slipping a disc is fixed by you getting cash...it's not, a far bigger disincentive would be a massive disproportionate fine against the company or body with the revenue going right into the health service, not into the local pub of people whos mates tell them "you'd get a claim outta dat boss".