Mathews gets OK to increase physical activityIt's been more than two weeks since Chargers head team doctor David Chao performed surgery on Ryan Mathews' right shoulder. Mathews went in Monday for a checkup.He got good news.The running back, already doing leg workouts, was cleared to begin upper-body exercises on his left side. He has consistently expressed confidence he'll be ready for the Sept. 10 season opener, and based what he took from his appointment, nothing derailed that optimism."He was using a lot of big words," Mathews said. "But he said everything is going good. He said just be patient with it. ..."It's right where I thought it would be. In two weeks, a bone is not going to be completely healed. But knowing my body, I think it's going right where it's supposed to be and it's going faster than normal."Mathews, 24, says he's doing about everything he can imagine to accelerate the healing process.He takes calcium pills.He eats right.Over his upper right chest, he sports a bone growth stimulator, a white patch that looks less like he's healing a broken clavicle and more like he's quitting cigarettes.Mathews said he wasn't told anything about the pace of his recovery as it relates to being back for Week 1. His goal stares straight into the headwind of the team's expectation, which is that he'll miss at least a game or two."But I feel I'll be ready," Mathews said. "I've been doing everything right. Eating right. Doing what I can. I think I'll be straight."