If its shinsplits you’ll know by running your hand up the shin/tendons by it (go fairly deep). It will be *incredibly* painful/tender on or right next to the shin, and feel kinda grisley to touch. I wouldn’t call shinsplints a jarring pain though and mine wasn’t right on the shin, it was very slightly off to the side of it (where the tendons/liagaments attached to it)
The tendons/muscles around my shins always got tight from running, an exercise to strengthen them from my physio: Lean with back against wall, drop down into a fairly deep squat so thighs are at knee level, keep back and head against wall and life toes/ball of your feet up towards your shin and lower down as slowly as you can, ideally for a count of 10.
Try using your fingers and oil to massage shin muscles instead of foam rollar which is what i do, its HORRIBLE but works (and its what physio would do too).
Take a few days of from running and then try the rule my physio gave me. If you run for 30mins and its ok/a little sore but the pain goes away after 30mins of finishing exercise, you can continue to run for 30mins a few times a week. If it doesn’t go away, rest up, then try a 15min run with the same pain/time rule and so on.
Otherwise get to a physio asap to get it sorted so you are fit for paris! 🙂