I see this as a massage therapist as a common issue among runners and have experienced this myself. Alongside thorough warm up and warm down and focussed stretching, regular sports/deep tissue massage can be beneficial to alleviate tightness.
Did you go straight back to hill running following your break? Change of footwear at all? Whilst RICE protocol is the right thing to do, it may also be worth looking at strengthening the tibialis posterior muscle (important stabiliser, contracts to prevent arch collapse and assists in plantar flexion), which when strengthened will help reduce the chance of further overuse/injury to tib anterior.