I offer up my pain or suffering, so that someone else’s may be relieved.
For example, one year, I (purposely) didn’t use the heater in my car between the parish church and my phone; it was very cold, and I offered it up for those that didn’t have heat, especially children.
If I have a headache, I might offer it for those suffering from brain injury, or mental illness. Let my ‘suffering’ take the place of theirs, even for just a moment.
If I’ve lost someone to death, I may offer my suffering for them, or for someone (nonspecific) who has no one to pray for them, or the souls in purgatory.
You can do this with any inconvenience or suffering. You can just offer it up, or ‘name’ who you are offering it up for, in my examples.
Hope that helps. I’ve talked this over both with my pastor and my Catholic therapist.