Jurisdiction Ohio Resident working weekdays in Arkansas

I'm an Ohio resident (8 years, own property, return home each weekend) working in Arkansas 6.5 days per week. I'm a W2 employee of a company that is Headquartered in VA. I was hired and am managed by department in Georgia. My worksite is AR w/reimbursement for weekly travel to/from AR and my income taxes are paid to the state of AR.

I've just found out that I'm being paid $20/hr less then my 2 male co-workers. This has been going on for 6+ months. All thee of us are on the same contract and do the exact same work and are managed by the same manager. My qualifications are actually stronger then the male counter parts (more experience, higher eduction degree and certifications).

I want to seek a resolution to this issue, but can't find any guidance for what Jurisdication/laws would apply. Would it be Ohio (where I signed the contract), AR where I work or one of their states?

I'm putting together my complaint and my goal is to submit to the HR of my company first to allow them a chance to resolve this without any other actions. (Can they force me to use their mediation instead of filing with the EEOC on this action if they don't correct the issue?) I would like to have an attorney before I submit the complaint, but have no idea of what state applies.