Add your frozen berries to a microwave-safe bowl. Microwave for 3 minutes, taking them out every minute to stir and mash them with a fork. Each time you do this they should be a bit easier to mash. (The bowl your berries are in will likely get very hot throughout this process, so use oven mitts when transferring back and forth to the microwave if needed).
Once the full 3 minutes are up, add your chia seeds, lemon juice, and maple syrup to the mashed frozen berries. Stir so everything is evenly incorporated. (At this point your jam mixture will be pretty runny, this is normal! It will thicken in the next step).
Allow you Chia Raspberry Jam to sit at room temperature for 15 minutes, and then transfer to the fridge and let sit for another 15 minutes. This allows your jam to thicken and chill.
Serve however you wish and enjoy!