I'm more comfortable in past tense, too, as are most writers (I think). If you're writing in past tense & want to do a flashback, just use some little "device" to indicate to the reader that something just changed. Here's an example from one of my stories (hope it formats like I wrote it). The speaker is telling a story to her friends & then flashbacks to the event.
“Though he was clearly no threat to me, I was suddenly afraid. I felt strange and I thought maybe that must be how it felt to die.”
“Are you ready to die, man?”
“… Am I not dead already?”
“No, you are not. Neither am I, though we are both on death’s road. Shall we fight to our ends?”
“Look at me, dragon. I have nothing left in me to fight with. And you do not seem so well, either. Has there ever been a truce between our kinds?”
“Not to fight. A promise not to hurt each other anymore… because we already are.”
“As soon as I heard those words, I knew what he was. This was the creature of my dream.”
I used tildes here but have used other tricks. Any sort of divider, change in fonts or indentation, italics, etc. will alert a reader that there's a change happening as the point of view shifts.